-Add lightmapper

-Fixes to unwrapper (remove degenerates), makes Thekla not crash
-Added optional cancel button in EditorProgress
-Added function to force processing of events (needed for cancel button)

scene/main/node.cpp

@@ -177,8 +177,8 @@ void Node::_propagate_ready() {
 	}
 	data.blocked--;
 	if (data.ready_first) {
-		notification(NOTIFICATION_READY);
 		data.ready_first = false;
+		notification(NOTIFICATION_READY);
 	}
 }