- Added code to check for waterfalls in all 8 cardinal directions

- Fixed bug in which swamp caused a false negative for the wall-rounding code
- Made directions into an enum, with an operator++ and two difference arrays (for x and y).
- Added case to wall-rounding code to handle a lone pillar of wall
- The block_horse flag is cleared when importing a poison or disease terrain, because horses can now not cross status-inflicting terrain at all.
- Added the book Finder icon

git-svn-id: http://openexile.googlecode.com/svn/trunk@64 4ebdad44-0ea0-11de-aab3-ff745001d230

osx/classes/terrain.cpp

@@ -250,7 +250,8 @@ cTerrain& cTerrain::operator = (legacy::terrain_type_type& old){
 	trans_to_what = old.trans_to_what;
 	fly_over = old.fly_over;
 	boat_over = old.boat_over;
-	block_horse = old.block_horse;
+	if(special == TER_SPEC_DANGEROUS) block_horse = false; // because it's now redundant and unhelpful
+	else block_horse = old.block_horse;
 	light_radius = old.light_radius;
 	step_sound = old.step_sound;
 	shortcut_key = old.shortcut_key;