Don't allow cart click while that cart is playing.

app/musicmuster.py

@@ -188,7 +188,10 @@ class Window(QMainWindow, Ui_MainWindow):
         """Handle cart click"""
 
         btn = self.sender()
+
         if helpers.file_is_readable(btn.path):
+            # Don't allow clicks while we're playing
+            btn.setEnabled(False)
             btn.player.play()
             btn.is_playing = True
             colour = Config.COLOUR_CART_PLAYING
@@ -272,6 +275,7 @@ class Window(QMainWindow, Ui_MainWindow):
                 if not btn.player.is_playing():
                     # Cart has finished playing
                     btn.is_playing = False
+                    btn.setEnabled(True)
                     # Setting to position 0 doesn't seem to work
                     btn.player = self.music.VLC.media_player_new(btn.path)
                     btn.player.audio_set_volume(Config.VOLUME_VLC_DEFAULT)