(svn r3232) -Add: implemented the event-system for AIs
-Add: added several hooks (event-callbacks) for road-related-stuff

(svn r3181) -Bracing
-Indentation
-Whitespace
-DeMorgan's Law
-Test with NULL or 0 for non-booleans
-'\0' instead of 0 for chars
-Remove redundantly redundant comments (like DoFoo(); // Do foo)
-Join multiple short lines with a single statement
-Split single lines with multiple statements
-Avoid assignments in if

(svn r3078) Some more stuff, which piled up:
- const, whitespace, indentation, bracing, GB/SB, pointless casts
- use the trinary operator where appropriate
- data types (uint[] -> AcceptedCargo, ...)
- if cascade -> switch
- if (ptr) -> if (ptr != NULL)
- DeMorgan's Law
- Fix some comments
- 0 -> '\0', change magic numbers to symbolic constants

(svn r3077) static, const, bracing, indentation, 0 -> '\0'/NULL, typos in comments, excess empty lines, minor other changes
nothing spectacular, just some stuff, which piled up

(svn r3073) int/byte -> EngineID/PlayerID/VehicleID
0/-1 -> INVALID_ENGINE
0x10 -> OWNER_NONE

(svn r2962) - const correctness for all Get* functions and most Draw* functions that don't change their pointer parameters
- change a lot of byte player types to PlayerID
- beautify header files, same "#endif /* filename */" ending

(svn r2951) - Fix: [ 1259345 ] Changing engine in netgame opens train window for everyone
- Add IsLocalPlayer() which substitutes _local_player == _current_player

(svn r2948) -Fix: the old AI needs a special flag that triggers all kind of special
abilities you really don't want to know about (free bridges, etc..)
I removed this flag some revisions ago, but the Aircraft part
depends on it, so I re-enabled it again..

(svn r2702) -Codechange: Cleaned up the sprite code and replaced many magic numbers
by enums. There remains work in gfx.c to move the "transparency" and
"recolor" bits around to make space for more sprites. However, 2800
additional sprites can now be loaded. There also remains cleanup and
Doxygen work on many of the header files.

(svn r2595) -Codechange: Introduced "IsSteepTileh" to find whether a tile is steep
(i.e. spans two height levels) and use it throughout the code.
-Codechange: Add CanBuildDepotByTileh to find if a tile is suitable to
build a depot on it. Wraps some bitmagic which seems quite unreadable at
first glance

(svn r2516) - Feature: [pbs] Implement path-based-signalling. This allows multiple trains within the same signal block, provided their paths dont intersect. For this the block must have all exit and entry signals be pbs signals. Place these by ctrl-clicking 4 times on a normal signal.
- Feature: [pbs] Implement autoplacement of pbs blocks, when a block has an entry and an exit pbs signal, covert the entire block to pbs. Can be turned off in the patch settings.
- Feature: [pbs] Allow showing of reserved status by making the tracks darker, when the pbs debug level is at least 1.

(svn r2448) General cleanup of rail related code, more to follow.
* Add: rail.[ch] for rail-related enums and wrapper functions.
* Codechange: Removed dozens of magic numbers with below enums.
* Codechange: Rewrote CheckTrackCombination().
* Add: TILE_SIZE, TILE_PIXELS and TILE_HEIGHT constants.
* Add: enums RailTileType, RailTileSubtype, SignalType to mask against the map arrays.
* Add: enums Track, TrackBits, Trackdir, TrackdirBits for railway track data. (Note that the old RAIL_BIT constants are replaced by TRACK_BIT ones).
* Add: enums Direction and DiagDirection
* Codechange: Moved a bunch of track(dir) related lookup arrays from npf.[ch] to rail.[ch].
* Codechange: move RailType enum from tile.h to rail.h.
* Add: Wrapper functions for masking signal status in the map arrays: SignalAlongTrackdir, SignalAgainstTrackdir and SignalOnTrack.
* Add: Wrapper functions to access rail tiles, using above enums
* Add: Wrapper functions to modify tracks, trackdirs, directions, etc.
* Add: Wrapper functions for all lookup arrays in rail.[ch] (Arrays are still used in parts of the code)
* Codechange: Renamed some variables and arguments to better represent what they contain (railbit -> track, bits -> trackdirbits, etc.).
* Codechange: Don't use FindLandscapeHeight() in CmdRemoveSingleRail(), since it returns way too much info. Use GetTileSlope() instead.
* Codechange: [NPF] Removed some unused globals and code from npf.c.

(svn r2288) - CodeChange: protected the next batch of commands (41 so far, out of 115).
- CodeChange: changed the airport gui airport-type checking. Added function GetValidAirports() that returns bitmasked availibility, is also used for checking.
- CodeChange: to check tree-planting, 2 const arrays have been moved to table/tree_land.h (type and count)
- CodeChange: added IsTownIndex() in following of IsStationIndex(), etc.
- Fix (regression): road tunnels did not work anymore, forgot that their type was 0x200 (documented now)

(svn r1863) Give the effect vehicle type enums more descriptive names and use the enum as parameter type for CreateEffectVehicle*()
-Fix: [1116619] Generate the correct smoke type for diesel trains

(svn r1831) -Fix: Scenario Editor now handles human-made roads better (try to build
a city layout before placing the city, finally that works very nice)

(svn r1817) -Codechange: Moved depot-functions to depot.c
-Codechange: Added wrappers around depot-access (GetDepot no exists)
-Codechange: Made depot-functions a bit more logic (no longer
GetDepotByTile crashes your game when you request it on a non-depot tile)
-Add: made depots dynamic (yes, 64k depots are possible now)

(svn r1785) -Fix: space-correctness in road_cmd.c, and one wrong line from last
commit (tnx to DarkVater)

(svn r1784) -Fix: removed ClosestTownFromTile where possible, or replaced it
with _map2-data if possible (Celestar / TrueLight)

(svn r1768) -Codechange: Store town index in _map2 of town tiles
Moved house type from _map2 to _map3_hi for MP_HOUSE
Moved foundation and roadworks from _map2 to _map3 for
MP_STREET
This increases game speed by a factor of around 15(!) if many cities are around.
Converting an old game is done automagically, but can take a while

(svn r1751) - Feature: New PathFinder (NPF).
- Supports trains, road vehicles and ships.
- Uses A* pathfinding (same codebase as the new ai).
- Currently unlimited search depth, so might perform badly on large maps/networks (especially ships).
- Will always find a route if there is one.
- Allows custom penalties for obstacles to be set in openttd.cfg (npf_ values).
- With NPF enabled, ships can have orders that are very far apart. Be careful, this will break (ships get lost) when the old pathfinder is used again.
- Feature: Disabling 90 degree turns for trains and ships.
- Requires NPF to be enabled.
- Ships and trains can no longer make weird 90 degree turns on tile borders.
- Codechange: Removed table/directions.h.
- table/directions.h contained ugly static tables but was included more than once. The tables, along with a few new ones are in npf.[ch] now. Better suggestions for a location?
- Fix: Binary heap in queue.c did not allocate enough space, resulting in a segfault.
- Codechange: Rewritten FindFirstBit2x64, added KillFirstBit2x64.
- Codechange: Introduced constant INVALID_TILE, to replace the usage of 0 as an invalid tile. Also replaces TILE_WRAPPED.
- Codechange: Moved TileAddWrap() to map.[ch]
- Add TileIndexDiffCByDir(), TileIndexDiffCByDir().
- Codechange: Moved IsTrainStationTile() to station.h
- Add: IsRoadStationTile() and GetRoadStationDir().

(svn r1718) Use the enum TileType as parameter/return type for [GS]etTileType() instead of plain int.
This makes it necessary to rename TileType() to GetTileType() because a type and a function may not share the same name.

(svn r1560) Introduce SetTileType() and SetTileHeight()
Replace direct references to _map_type_and_height with these

(svn r1288) -Codechange: changed _map2 to an uint16. It is still saved and loaded as
an uint8 till the savegame version is bumped to version 5. Then it works
automaticly as a fully uint16. So _stations[] can not be increased till
after the bump!!

(svn r925) Use sound enums
Also play the correct sound when a toyland road vehicle breaks down

(svn r901) Small step in the process to clean up the DPARAM mess:
- reduce to 2 sizes (*DParam64 for 64bit values, *DParam for the rest)
- use inline functions instead of macros
- add assert()s to check for buffer overruns

(svn r815) Include strings.h only in the files which need it.
This should reduce the compile time after altering english.txt by about 1/3, because "only" 62 instead of 90 .c files must be recompiled.

(svn r787) Invert the sense of the DO_TRANS_BUILDINGS flag to be consistent with its own name and all other DO_* flags.
Now it is active-true.

(svn r724) Remove restriction that a tile can only accept 3 cargo types.
This especially enables houses to accept passengers, mail, goods AND food.
Add string templates for up to 5 cargo types for the tile info window. If more are needed just add them.
Simplify (de-uglify) the logic for cargo acceptence for houses and split the goods/food table into two. The acceptance is unmodified, but accepting goods AND food is now trivially possible. The exact amounts have to be decided.
This is based on Celestar's changes in the map branch plus some further bits that will be merged there soon.

(svn r607) -Patch: [ 985102 ] static cleanup
Thanks to lvoge

(svn r513) Merge revisions 402, 416, 417, 478, 479, 511, 512 from map to trunk
This includes 2 fixes
-Fix: [1048596] Monorail and Maglev sounds are swapped (r511)
-Add special case to load the jackhammer sound (r478)
The rest are cleanups und enumeration to make merging possible/easier

(svn r242) -Fix: Pathfinding bug for road vehicles introduced in r160 fixed (blathijs)
-Fix: Pathfinding under bridges bug for ships introduced in r160 fixed (Darkvater)

(svn r223) -Fix: Const correctness and miscellaneous fixes. Thank you Tron for your diligent fixing of warnings (and some possibly bugs) (Tron)
-CodeLayout: Remove trailing spaces and Windows linebreaks

(svn r202) -Codechange: I missed some files with trailing spaces.. this should be
all ;)

(svn r160) -Codechange: made GetTileTrackStatus more readable (blathijs)
-Fix: some minor fixes around GetTileTrackStatus (blathijs)

(svn r150) -Fix: [1010833] Turning on the magic bulldozer removes oil rigs
-Fix: [993493] Buildings on water
-Feature: Water floods everything, including vehicles.

(svn r85) -Add: initial commit of new AI (enable in Patch menu)
-Add: generalised A* Algorithm
-Add: generalised queues (Fifo, Stack, InsSort, BinaryHeap)