move floating globals into a namespace

stepmania/src/GameLoop.cpp

@@ -109,7 +109,7 @@ void GameLoop()
 
 		/* If we don't have focus, give up lots of CPU. */
 		// XXX: do this in DISPLAY EndFrame?
-		if( !AppHasFocus() )
+		if( !StepMania::AppHasFocus() )
 			usleep( 10000 );// give some time to other processes and threads
 #if defined(_WINDOWS)
 		/* In Windows, we want to give up some CPU for other threads.  Most OS's do