TileConstants: impl isIndestructible2(), slightly different than isIndestructible()

the difference is whether RUBBLE is included or not;
TODO- make a better name

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@799 d9718cc8-9f43-0410-858b-315f434eb58c

src/micropolisj/engine/MapScanner.java

@@ -503,8 +503,7 @@ class MapScanner
 		{
 			for (int x = xpos-1; x <= xpos+1; x++)
 			{
-				char c = (char)(city.map[y][x] & LOMASK);
-				if (c >= FLOOD && c < ROADBASE) {
+				if (isIndestructible2(city.getTile(x,y))) {
 					// radioactive, on fire, or flooded
 					return false;
 				}