(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 r5943) -Merge TGP (part r5725): -Codechange: renamed Thread to OTTDThread, as Windows
(who else) uses Thread in winbase.h, and starts complaining if you define it
otherwise (with weird, undefined errors) (tnx Arnau and Rubidium)

(svn r2810) Threads may now return information when they terminate using a void*.
Also add the new files to the MSVC project files.