fixes #61, preparing updatewallpaper to be moved

--update wallpaper will go to the workareas data engine. I found
that wallpapers for normal activities can be found with out issues
without using containment(). For the add new activity through
the data engine there is no problem. For the "clone activity" the
only thing that has to be made is to disable the updatewallpaper
mechanism... :) In the new activity the background is the same
with the old one from which was copied... :)
update wallpapers in now ready for the dataengine

--cloning support could also move to the dataengine but
the signal that triggers the progress dialog can not be
used that way. At the same time I think it could be
better to hide a bit the clonning support because it is not
the best of the implementations...
Workareas data engine is here and functional...

--Data engine is here and keeps in sync all the data about
workareas. Someone can add two workflow plasmoids and the
workareas will be all the time synced...
--next steps are activities ordering and selection mechanism
now that the engine is ready. For the ordering an Order field
can be added to the workareas data engine. After that Ordering
can be done based on this field in the ActivitiesEnhancedModel
fixes syncing between desktops and workareas

--desktops follow the workareas max number,
I am thinking about a Passive and Active mode for
workareas, in order for the user to be able to choose
the behavior. Passive mode could be that VDs are in
higher value for consistency instead of workareas.
Even though a pager is now easy for someone implement
as the workareas data engine exists.