(svn r6739) -Fix (r6001): Crash on removing farmland belonging to a farm. The search would loop
around the edges causing some troubles. Also make sure that the land after
farm removal is not barren but 2/3rd grass. Better suited.

(svn r6407) -Fix: Check return values of DoCommand() with CmdFailed and that of DoCommandP
with a boolean type.

(svn r6406) -Codechange: Rename TileOffsByDir to TileOffsByDiagDir because it accepts
DiagDirections, and add TileOffsByDir that handles Directions.
-Codechange: Make the treeloop use TileOffsByDir().

(svn r6001) -Feature: when removing a farm, his farmland is removed too (over time) (based on peter1138's patch, FS#82)
To make this to work, in older games farmland is removed on load, and replanted

(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 r5365) -Fix: It was possible to dig into a tunnel if certain rail combinations were ontop of it
(Hopefully this time it works for real)

(svn r5363) Revert 5312, 5288, 5248, 3992, 3249, 3228
They were all aimed at fixing the terraform-into-tunnel problem, but introduced new sideeffects while doing so

(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 r4572) Remove vehicle_leave_tile_proc
There's exactly one implemented function (unbarring a level crossing) and one place where it can be triggered (a train leaves a level crossing)
It's a bit overkill, so just handle this one case where it can happen

(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 r3992) -Fix: Rewrote the code to determine whether a rail-tile can be terraformed.
Fixes a bug where you could terraform a tunnel (fixed by r3228, but reverted that one)
Fixes a bug introduced by r3228 which allowed steep rail tiles resulting in ... unwanted effects such as display artifacts.
That means the terraform feature should not work as intended; it also uses _valid_tileh_slopes to determine valid configurations instead of hand-brewn stuff.
TODO: _terraform_err_tile and similar TileIndices should have INVALID_TILE as "unused", not 0. (0 is a valid tile).

(svn r3564) Several smaller changes:
- Don't treat non-booleans as booleans
- Reduce variable scope
- Bracing
- Use DeMorgan's law to make conditionals easier to read
- if cascade -> switch
- Replace some magic numbers by symbolic names
- Avoid assignments within other statements

(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 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 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 r2300) - CodeChange: check the last number of commands, now only the refit ones remain, and some server-only commands.
- CodeChange: remove cmd-misuses CmdStartScenario() and CmdDestroyCompanyHQ()
- Fix (invisible): when parameter checking CmdRestoreOrderIndex() the vehicle did not have its orders yet, so it would fail. So move doing this until AFTER the orders have been added back in RestoreVehicleOrders()

(svn r2286) - CodeChange: paramcheck the next batch of commands.
- Fix (regression): fix up terraform land where every player can terraform land (towns, map generation), and player can terraform different corners; used for building tunnels

(svn r2075) -Fix: added missing breaks in switches
-Fix: added const for a const variable

(svn r1797) Clean up TileLoopClearHelper() a bit:
- if cascades -> switch
- uint -> TileIndex
- (uint)-1 -> INVALID_TILE
- don't treat non-flags as flags

(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 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 r1386) Move TileIndexDiff to map.h
Move _tileoffs_by_dir to map.[ch] and encapsulate it in TileOffsByDir()

(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 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 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 r526) -Fix: [1035303] bug about lowering tracks built on slopes
While here make sure that the failing tile gets a red error marker

(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.