replace q method calls with bluebird ones

```
find src test -name '*.js' |
    xargs perl -i -pe 's/q\.(all|defer|reject|delay|try|isFulfilled)\(/Promise.$1(/'
```

src/VectorConferenceHandler.js

@@ -53,7 +53,7 @@ ConferenceCall.prototype._joinConferenceUser = function() {
     // Make sure the conference user is in the group chat room
     var groupRoom = this.client.getRoom(this.groupRoomId);
     if (!groupRoom) {
-        return q.reject("Bad group room ID");
+        return Promise.reject("Bad group room ID");
     }
     var member = groupRoom.getMember(this.confUserId);
     if (member && member.membership === "join") {