(svn r5946) -Add: merged the TGP branch to mainline. TGP adds:
- New optional landscape generator (TerraGenesis Perlin)
- Load heightmaps (either BMP or PNG)
- Progress dialog while generating worlds (no longer a 'hanging' screen)
- New dialogs for NewGame, Create Scenario and Play Heightmap
- Easier to configure your landscape
- More things to configure (tree-placer, ..)
- Speedup of world generation
- New console command 'restart': restart the map EXACTLY as it was when you
first started it (needs a game made after or with this commit)
- New console command 'getseed': get the seed of your map and share it with
others (of course only works with generated maps)
- Many new, world generation related, things
- Many internal cleanups and rewrites
Many tnx to those people who helped making this:
Belugas, DaleStan, glx, KUDr, RichK67, Rubidium, and TrueLight (alfabetic)
Many tnx to those who helped testing:
Arnau, Bjarni, and tokai (alfabetic)
And to all other people who helped testing and sending comments / bugs
Stats: 673 lines changed, 3534 new lines, 79 new strings

(svn r5070) Merged the bridge branch
-Feature: Bridges can now be placed above:
Any railway track combination (excluding depots and waypoints)
Any road combination (excluding depots)
Clear tiles (duh), including fields
Tunnel entrances
Bridge heads

Thanks to Tron for idea and implementation, KUDr for the yapf synchronization and many others for hours of testing

There are still a number of visual problems remaining, especially when electric railways are on or under the bridge.
DO NOT REPORT THOSE BUGS FOR THE TIME BEING please.

(svn r4342) Change the first two parameters of commands - virtual pixel coordinates of the tile to operate on - to a TileIndex
Remove DoCommandByTile(), because now it does the same as DoCommand()

(svn r4028) The last external user of FindLandscapeHeightByTile() is gone (r4027).
Move its implementation into its only caller - FindLandscapeHeight() - and remove it

(svn r3514) -Codechange: Replace direct fiddling of bits for the ground type and density of clear tiles with symbolic names and accessors.
See clear.h for details

(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 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 r2564) Fix: Fixed conceptual issue in network_gui.c. AllocateName is not meant to be used by GUI-code, because it modifies the "game-state".
Added a way to bind a C-string to an openttd string which doesn't modify the game state.

(svn r2560) Fix: various minor code changes.
Added RandomTile/RandomTileSeed functions to generate a random tile.
Changed landscape routines so they don't assume that the Y map side is a power of two. (support for this is not complete, though)
Changed some frequently used map macros to not compute the values each time.
Silence some warnings on MSVC.

(svn r2297) - CodeChange: server-check the next batch of commands.
- CodeChange: since only the server will be able to modify difficulty settings, leave the checking of correct values besides, and trust users will join legit servers.
- CodeChange: for renaming signs, only check if GetDParam(); eg _decode_parameters is empty ('\0') or not, instead of the extra check of players, etc. That basically does the same thing. Also dirty sign two times when renaming, once before, once after the action. Because if the name becomes shorter and you update only after, garbage remains on the screen.
- CodeChange: made GetMaskOfTownActions() available to the town-cmd to double-check if the action was available to the player. For this purpose the hardcoded _local_player has been removed from the function and is now passed as a parameter.

(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 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 r1706) Implement ScaleByMapSize() and ScaleByMapSize1D()
These scale a number relative to the map size/circumference.
Use them to scale the amount of map objects.
Of course at the moment they return just the input, because there are no bigger/smaller maps yet.

(svn r1697) Remove superflous special case for the VOID border tiles in FindLandscapeHeightByTile()
While here clean up some other stuff: uint -> TileIndex, assert() that the TileIndex is valid and remove a line which was already commented out

(svn r1676) Increase the size of TileIndex and TileIndexDiff to 32bits and adapt the save/load data and some other parts of the code to that change

WARNING: If i made any mistake here it WILL lead to corrupted savegames!

(svn r1641) Remove a boundary check added in r1332 to work around a bug - the real cause has been eleminated in r1413.
Leave an assert() just to be sure...

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

(svn r1545) Add TileHeight() which returns the height (not multiplied by 8)
Replace some direct references to _map_type_and_height with TileHeight()/IsTileType()

(svn r1415) Move TILE_FROM_XY and TILE_XY to map.h and push TILE_[XY] bits from map.h into map.c.
Now the whole source except map.c is independent of TILE_[XY]_BITS!

(svn r1337) Use MapMax[XY]() (or MapSize[XY]() if appropriate) instead of TILE_MAX_[XY]
While here replace one erroneous TILE_MAX_X with MapMaxY()

(svn r1332) -Fix: Desert-landscape does no longer crash (protected GetMapExtraBits
from overflowing)

(svn r1321) -Fix: Revision 1302 partly solved the problem and created an other.
Should now really be solved.. now only MP_WATER is owned by OWNER_WATER

(svn r1302) -Fix: [ 1091655 ] In some older maps somehow water is owned by
OWNER_NONE instead of OWNER_WATER.
-Fix: On InitializeLandscape the map was made MP_WATER, but OWNER_NONE.
When ConvertGroundTilesIntoWaterTiles() is not called, this gives big
problems (see above). Now the owner is set to OWNER_WATER by default.

(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!!