added mpd_stop, mpd_vol_min, mpd_vol_max, mpd_vol_med

rfidac/data/_mpd_helper

@@ -34,6 +34,22 @@ function mpd_play_shuffle {
   $mpc play 1
 }
 
+function mpd_stop {
+  $mpc stop
+}
+
+function vol_min {
+  mpd_set_volume 5
+}
+
+function mpd_med {
+  mpd_set_volume 50
+}
+
+function mpd_vol_max {
+  mpd_set_volume 75
+}
+
 function mpd_set_volume {
   if [ -n "$1" ]; then # non-zero length
     $mpc volume $value