Multi monitor support.

Hi, this is the change with multi monitor support. It allows you to choose the monitor where you want the guake to appears. Also there is the option to window appear on the current mouse cursor monitor.

I tested it on Ubuntu 12.10 64bit with Unity. It works fine.
Let me know if you have any other questions regarding this change.

PS. no additional library, no additional view, window, etc...

Best Regards,
Kostya.