New Awn background: Floaty!

Today I decided to take a stab at implementing new background style for Awn, it's pretty similar to "flat" background - code- and also look-wise, so it was pretty easy to do it.
Hopefully this will make more people happy, as this feature was requested a couple of times on our bug tracker.

Anyway kudos to wbar quys, cause it seems they had a background like this in their dock first.

And of course an obligatory screenshot:


And here's another screenshot of how it looks on the desktop: