[host] converted program to a windows hidden/background user app.

NvFBC will not start when running as a service, likely intentional
security of the API to prevent it from being abused.

host/Service.h

@@ -19,7 +19,7 @@ public:
 
   bool Initialize();
   void DeInitialize();
-  bool Process(HANDLE stopEvent);
+  bool Process();
 
 private:
   static Service * m_instance;