Numerous changes to terrain and trim. The changes to the scneario editor work as expected.

- New way of drawing walkway (doesn't work yet)
- New way of drawing roads (doesn't yet work correctly)
- New way of drawing trim (not tested yet)
- New way of handling marked specials (works in editor but not in game)
- New way of handling two-space rubble in the editor (works as expected)
- Merged several terrain special properties
- Deprecated several terrain graphics
- Completed (probably) the import & convert code for old-format terrain
- Probably other things that I have forgotten that have something to do with terrain
- A few other little things, bugfixes, etc

git-svn-id: http://openexile.googlecode.com/svn/trunk@56 4ebdad44-0ea0-11de-aab3-ff745001d230

osx/boe.main.cpp

@@ -1330,7 +1330,7 @@ void move_sound(unsigned char ter,short step){
 	}else on_swamp = false;
 	
 	if ((monsters_going == false) && (overall_mode < MODE_COMBAT) && (univ.party.in_boat >= 0)) {// is on boat ?
-		if (spec == 21) //town entrance ?
+		if (spec == TER_SPEC_TOWN_ENTRANCE) //town entrance ?
 			return;
 		play_sound(48); //play boat sound
 	}