Allow the clearing of the tile manager's cache.

git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@110 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/media/tile/TileManager.java

@@ -123,6 +123,14 @@ public class TileManager
         return uts;
     }
 
+    /**
+     * Clears any cached tilesets.
+     */
+    public void clearCache ()
+    {
+        _handcache = new HashMap();
+    }
+
     /**
      * Sets the tileset repository that will be used by the tile manager
      * when tiles are requested by tileset id.