FIXED bug when quitting app

The "Quit" action did not quit the application, it just closed
the main window. Some specific action dialogs were therefore not closed
(e.g. the volume rendering or rigid mesh transform dialog).
Now ensure as well that the modified components are not deleted without
asking the user if she/he wants to save them (abort is also possible
thanks to the "Close All" action

sdk/actions/application/QuitAction.cpp

@@ -57,7 +57,16 @@ QWidget* QuitAction::getWidget() {
 
 // --------------- apply -------------------
 Action::ApplyStatus QuitAction::apply() {
-    Application::getMainWindow()->close();
-    return SUCCESS;
+    // close all components (and therefore ask the user to savet the modified ones)
+    ApplyStatus closeAllStatus = Application::getAction("Close All")->apply();
+    if (closeAllStatus == SUCCESS) {
+        // Quit the app (will call Application::quitting() and therefore unload all action extensions and delete all actions)
+        Application::quit();
+        return SUCCESS;
+    }
+    else {
+        // or abort the operation
+        return ABORTED;
+    }
 }