(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

openttd.h

@@ -77,14 +77,17 @@ enum SwitchModes {
 	SM_GENRANDLAND = 6,
 	SM_LOAD_SCENARIO = 9,
 	SM_START_SCENARIO = 10,
+	SM_START_HEIGHTMAP = 11,
+	SM_LOAD_HEIGHTMAP = 12,
 };
 
 
 /* Modes for GenerateWorld */
 enum GenerateWorldModes {
-	GW_NEWGAME  = 0,    /* Generate a map for a new game */
-	GW_EMPTY    = 1,    /* Generate an empty map (sea-level) */
-	GW_RANDOM   = 2,    /* Generate a random map for SE */
+	GW_NEWGAME   = 0,    /* Generate a map for a new game */
+	GW_EMPTY     = 1,    /* Generate an empty map (sea-level) */
+	GW_RANDOM    = 2,    /* Generate a random map for SE */
+	GW_HEIGHTMAP = 3,    /* Generate a newgame from a heightmap */
 };
 
 /* Modes for InitializeGame, those are _bits_! */
@@ -410,6 +413,9 @@ enum {
 	WC_HIGHSCORE = 0x4D,
 	WC_ENDSCREEN = 0x4E,
 	WC_SIGN_LIST = 0x4F,
+	WC_GENERATE_LANDSCAPE = 0x50,
+	WC_GENERATE_PROGRESS_WINDOW = 0x51,
+	WC_OK_CANCEL_QUERY = 0x52,
 };