clearer messages between Monitor and Controller

"add" was very generi, and is easy to get confused with other part of the code;
uris_enqueue is clearer, more unique, therefore more "greppable"

larigira/event.py

@@ -154,7 +154,7 @@ class Monitor(ParentedLet):
                           'registry; this is most likely a bug'.
                           format(timespec.get('nick', timespec.eid)))
         uris = audiogenerate(audiospec)
-        self.send_to_parent('add', dict(uris=uris,
+        self.send_to_parent('uris_enqueue', dict(uris=uris,
                                                  audiospec=audiospec,
                                                  aid=audiospec.eid))
 

larigira/mpc.py

@@ -116,7 +116,7 @@ class Controller(gevent.Greenlet):
                 gevent.Greenlet.spawn(self.player.check_playlist)
             elif kind == 'mpc':
                 pass
-            elif kind == 'add':
+            elif kind == 'uris_enqueue':
                 try:
                     self.player.enqueue(args[0])
                 except AssertionError: