added "new map" button

fixed minor model/logic issues

mapview/model/MapModel.h

@@ -53,10 +53,17 @@ public:
 
 	/** create a new, empty root node */
 	void startEmpty() {
+
+		emit aboutToReset();
+		cleanup();
+
 		im = new Floorplan::IndoorMap();
 		root = new MMRoot(nullptr, im);
 		root->addListener(this);
 		//root->addSublayer(new MMFloors(root, im));
+
+		emit reset();
+
 	}
 
 	void cleanup() {