Wallpaper plugins

[Petri Damstén]

Hi,

I have been working on Plasma::Wallpaper and patch was getting big. Since 
there are some svn moves coming we agreed with Aaron that I should commit it 
now and continue to work on it in trunk. Sorry for not posting some earlier 
versions for comments.

Committed changes:
- Wallpaper API changes discussed in plasma-devel.
- Remove background painting from desktop containment.
- Remove desktop configuration from desktop containment.
- Add Image (Single image and Slideshow) wallpaper plugin (converted from 
desktop containment).
- Configuration to color wallpaper plugin.
- Add Desktop configuration to desktop view (converted from desktop 
containment).
- Desktop containment selection.

Wallpaper plugins have been working pretty good on my machine for some days. 
Desktop containment selection has more problems (Code in 
View::swapContainment). Some of the problems:
- Containment gets wrong geometry (after restart it's not on screen).
- Dataengine connection seems to break when containment changed
- Other containments don't have desktop settings... Should containments have 
default desktop menu when selected for desktop (+ what they already have)?

So any testing/help on this is welcome.

Petri