MSVC12 compiler compability fixes

include/Game/FPSCounter.h

@@ -1,6 +1,8 @@
 #ifndef GUI_FPSCOUNTER_H__
 #define GUI_FPSCOUNTER_H__
 
+#include <numeric>
+
 #include "GUI/Frame.h"
 #include "GUI/NumberFrame.h"
 

include/Game/HUD.h

@@ -59,6 +59,7 @@ private:
 	bool OnScore(const Events::ScoreEvent& event)
 	{
 		m_ScoreNumberFrame->SetNumber(m_ScoreNumberFrame->Number() + event.Score);
+		return true;
 	}
 };