xfdesktop testing stuff

[Brian J. Tarricone]

Hey all,

I just committed some experimental support for xrandr 1.2 (hot-plugging
monitors) to xfdesktop svn trunk.  The upside is that it was very easy
to do; the downside is that you need gtk 2.13.0 or above to use it.  As
I'm not really in the mood to break my system, and I'm not even sure
that the external monitor port on my laptop works, I haven't tested it.

For starters, I want to make sure nothing broke.  If you have a
multi-head setup and are using xfdesktop svn, please update and tell me
if it still works ok.  I also maybe (maybe!) fixed the 'stretch backdrop
across all monitors' option, so test that as well, I guess.

If you're incredibly brave (read: foolish) and want to install
gtk 2.13.0 and report back as to whether adding and removing monitors
works, that would be cool too.

	-brian