(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

gui.h

@@ -64,6 +64,10 @@ void ShowPlayerAircraft(PlayerID player, StationID station);
 /* terraform_gui.c */
 void ShowTerraformToolbar(void);
 
+/* tgp_gui.c */
+void ShowGenerateLandscape(void);
+void ShowHeightmapLoad(void);
+
 void PlaceProc_DemolishArea(TileIndex tile);
 void PlaceProc_LevelLand(TileIndex tile);
 bool GUIPlaceProcDragXY(const WindowEvent *we);
@@ -103,7 +107,6 @@ void SetVScroll2Count(Window *w, int num);
 void SetHScrollCount(Window *w, int num);
 
 void ShowCheatWindow(void);
-void AskForNewGameToStart(void);
 
 void DrawEditBox(Window *w, querystr_d *string, int wid);
 void HandleEditBox(Window *w, querystr_d *string, int wid);
@@ -138,6 +141,7 @@ enum {
 bool DoZoomInOutWindow(int how, Window *w);
 void ShowBuildIndustryWindow(void);
 void ShowQueryString(StringID str, StringID caption, uint maxlen, uint maxwidth, WindowClass window_class, WindowNumber window_number, CharSetFilter afilter);
+void ShowQuery(StringID caption, StringID message, void (*ok_cancel_callback)(bool ok_clicked), WindowClass window_class, WindowNumber window_number);
 void ShowMusicWindow(void);
 
 /* main_gui.c */