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/Scenario Editor/scen.actions.h

@@ -28,7 +28,7 @@ void change_val_4 (unsigned char *val,short a,short b,short c,short d);
 void change_val (unsigned char *val,short a,short b);
 void frill_up_terrain();
 void unfrill_terrain();
-void set_terrain(location l,unsigned char terrain_type);
+void set_terrain(location l,unsigned short terrain_type);
 bool fix_rubble(location l);
 bool fix_cave(location l);
 bool fix_mountain(location l);
@@ -67,3 +67,5 @@ void set_special(location spot_hit);
 bool save_check(short which_dlog);
 void update_item_menu();
 
+unsigned short get_ground_from_ter(unsigned short ter);
+bool terrain_matches(unsigned char x, unsigned char y, unsigned short ter);