(svn r2112) -Fix: ExtMidi no longer halts the game while starting a song

-Fix: Redirect stdin/stdout/stderr of the ExtMidi process to /dev/null, to prevent it from writing to the terminal
While here give the ExtMidi functions canonical names

music_gui.c

@@ -181,7 +181,7 @@ void MusicLoop(void)
 	if (_song_is_active == false)
 		return;
 
-	if (!_music_driver->is_song_playing()) {
+	if (!_music_driver->is_song_playing() && _game_mode != GM_MENU) {
 		StopMusic();
 		SkipToNextSong();
 		PlayPlaylistSong();