[Enhancement] Show the avatar in the notifications

[Contribucious]

The notification should show the avatar rather than the Birdie icon.

See screenshot: http://i.imgur.com/Ij3v0GL.png

P.S.: Also, but I think it's not possible if using "Notify OSD" for the notifications sadly, remove the little sentence at top right of notifications (the begin of the tweet content followed by "…"), as already shown fully just below. It's not useful and make the notifications overfilled unnecessarily. And as we don't have much time to understand what happens then read before disappear, especially if we've notifications from other programs at the same time (or multiple notifications from Birdie itself, even if personally I've never had more than one as reported as bug some days ago), removing the unnecessary content is great I think, to make the notifications more light and quicker to read (easily), as in Echofon for Mac for example (which uses Growl for the notifications). By the way, sadly, seems that we can't set "10 seconds" (for example) for the notification duration (in general, not Birdie specific I mean here), even with a third party tool as already tested. Too bad because the notifications disappear too quickly according to me.

TECHNICAL INFORMATION:
OS: Ubuntu 12.04.2 LTS (with Cinnamon)
Birdie version used: the r268 from the DAILY repository