core/reloader: trigger postReload with a signal

A signal is now used over the previous tree-searching method as some
QML components such as Repeater fail to reparent created children to
themselves, which breaks the tree.

src/core/generation.hpp

@@ -75,6 +75,7 @@ public:
 signals:
 	void filesChanged();
 	void reloadFinished();
+	void firePostReload();
 
 public slots:
 	void quit();