[main] Redraw on click

Whenever a module in the bar is clicked, immediately redraw the line, to
make for a snappier user experience (especially when muting/unmuting).

bumblebee/output.py

@@ -1,9 +1,15 @@
 
 class Output(object):
-    def __init__(self, theme):
+    def __init__(self, refresh, theme):
         self._theme = theme
+        self._refresh = refresh
         self._callbacks = {}
 
+    def redraw(self):
+        self._refresh.acquire()
+        self._refresh.notify()
+        self._refresh.release()
+
     def add_callback(self, cmd, button, module=None):
         if module:
             module = module.replace("bumblebee.modules.", "")