Global: Cleanup virtual/override specifiers.

Also missing virtual destructors, hidden non-overrides, etc.

Core/ThreadEventQueue.h

@@ -28,6 +28,8 @@ template <typename B, typename Event, typename EventType, EventType EVENT_INVALI
 struct ThreadEventQueue : public B {
 	ThreadEventQueue() : threadEnabled_(false), eventsRunning_(false), eventsHaveRun_(false) {
 	}
+	virtual ~ThreadEventQueue() {
+	}
 
 	void SetThreadEnabled(bool threadEnabled) {
 		threadEnabled_ = threadEnabled;