Stops the running game. This will cause the thread that called Run to
return. The value of 'errorCode' determines the value of 'returnCode'
that will be returned from Run.
Forces the application to shut down, displaying the given error message.
If no Application has been created, then the system level shutdown
procedure will be called. This is only to be used in the case of a fatal
error. Execution will return from this procedure, so plan accordingly.