Notifications management and rendering refactoring.

With warning notification Model out of bed reworked to not show after dismiss.

src/slic3r/GUI/GLCanvas3D.hpp

@@ -743,7 +743,8 @@ public:
     void msw_rescale();
 
     void request_extra_frame() { m_extra_frame_requested = true; }
-    void request_extra_frame_delayed(int miliseconds);
+    
+    void schedule_extra_frame(int miliseconds);
 
     int get_main_toolbar_item_id(const std::string& name) const { return m_main_toolbar.get_item_id(name); }
     void force_main_toolbar_left_action(int item_id) { m_main_toolbar.force_left_action(item_id, *this); }