desktop: recalculate the set wallpaper default color when disabling vera-control-lock.
Launcher: added a preliminary version.

This is still rough, and the pages doesn't work well.
But hey, it somewhat works!
Yay!
schema: added background-search-paths, background-include and background-exclude settings.

They are all arrays, and will be used by the control center module to obtain the list
of available wallpapers.
tutorial: set top and bottom margin on the tutorial.
0.22
Merge branch 'master' into debian
0.22-1