If video backend initialization fails, have the emulator die gracefully instead of crashing the application. Also a little clean up of the passage of the video window handle to the backend and back.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@7248 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Plugins/Plugin_VideoDX11/Src/VideoBackend.h

@@ -9,7 +9,7 @@ namespace DX11
 
 class VideoBackend : public VideoBackendHLE
 {
-	void Initialize();
+	bool Initialize(void *&);
 	void Shutdown();
 
 	std::string GetName();