(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

string.c

@@ -65,18 +65,15 @@ void str_validate(char *str)
 		if (!IsValidAsciiChar(*str, CS_ALPHANUMERAL)) *str = '?';
 }
 
-void strtolower(char *str)
-{
-	for (; *str != '\0'; str++) *str = tolower(*str);
-}
-
-/** Only allow valid ascii-function codes. Filter special codes like BELL and
- * so on [we need a special filter here later]
+/**
+ * Only allow certain keys. You can define the filter to be used. This makes
+ *  sure no invalid keys can get into an editbox, like BELL.
  * @param key character to be checked
- * @return true or false depending if the character is printable/valid or not */
+ * @param afilter the filter to use
+ * @return true or false depending if the character is printable/valid or not
+ */
 bool IsValidAsciiChar(byte key, CharSetFilter afilter)
 {
-	// XXX This filter stops certain crashes, but may be too restrictive.
 	bool firsttest = false;
 
 	switch (afilter) {
@@ -84,8 +81,9 @@ bool IsValidAsciiChar(byte key, CharSetFilter afilter)
 			firsttest = (key >= ' ' && key < 127);
 			break;
 
-		case CS_NUMERAL://we are quite strict, here
-			return (key >= 48 && key <= 57);
+		/* We are very strict here */
+		case CS_NUMERAL:
+			return (key >= '0' && key <= '9');
 
 		case CS_ALPHA:
 		default:
@@ -93,7 +91,13 @@ bool IsValidAsciiChar(byte key, CharSetFilter afilter)
 			break;
 	}
 
+	/* Allow some special chars too that are non-ASCII but still valid (like '^' above 'a') */
 	return (firsttest || (key >= 160 &&
 		key != 0xAA && key != 0xAC && key != 0xAD && key != 0xAF &&
 		key != 0xB5 && key != 0xB6 && key != 0xB7 && key != 0xB9));
 }
+
+void strtolower(char *str)
+{
+	for (; *str != '\0'; str++) *str = tolower(*str);
+}