Enhanced Tiled integration. Can now reload a map that has changed

externaly. Still some rough edges, notably the number of nitification
sto skip when saving in ATCS.

src/com/gpl/rpg/atcontentstudio/model/maps/ScriptArea.java

@@ -42,6 +42,7 @@ public class ScriptArea extends MapObject {
 	@Override
 	public void elementChanged(GameDataElement oldOne, GameDataElement newOne) {
 		if (oldOne == dialogue) {
+			oldOne.removeBacklink(parentMap);
 			dialogue = (Dialogue) newOne;
 			newOne.addBacklink(parentMap);
 		}