Stop passing our single DecoderControl object everywhere

This at least makes the argument list to a lot of our plugin
functions shorter and removes a good amount of line nois^W^Wcode,
hopefully making things easier to read and follow.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7353 09075e82-0dd4-0310-85a5-a0d7c8717e4f

src/main.c

@@ -431,7 +431,7 @@ int main(int argc, char *argv[])
 	initZeroconf();
 
 	openVolumeDevice();
-	decoderInit(&getPlayerData()->decoderControl);
+	decoderInit();
 	playerInit();
 	read_state_file();