(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

window.h

@@ -304,6 +304,16 @@ typedef struct querystr_d {
 } querystr_d;
 assert_compile(WINDOW_CUSTOM_SIZE >= sizeof(querystr_d));
 
+typedef struct query_d {
+	StringID caption;
+	StringID message;
+	WindowClass wnd_class;
+	WindowNumber wnd_num;
+	void (*ok_cancel_callback)(bool ok_clicked);
+	bool calledback;
+} query_d;
+assert_compile(WINDOW_CUSTOM_SIZE >= sizeof(query_d));
+
 typedef struct {
 	byte item_count;      /* follow_vehicle */
 	byte sel_index;       /* scrollpos_x */