Mrntt: Call shutdownSalmanoff after exiting main loop

We moved initializeSalmanoff and shutdownSalmanoff into
salmanoff.cpp. Now we also invoke shutdownSalmanoff when exiting
to destroy subsystems and components gracefully.

This fixes the segfault that was thrown on every program exit
when xcbWindow had captured a window.

smocore/include/marionette/marionette.h

@@ -28,8 +28,6 @@ struct CrtCommandLineArgs
     static void set(int argc, char *argv[], char *envp[]);
 };
 
-void initializeSalmanoff(void);
-
 } // namespace smo
 
 #endif // _MARIONETTE_H