New ProjectModel implementation

[Andreas Pakulat]

Hi,

just to let you know, I've just merged the rewrite of the projectmodel
API I've worked on into master. Its now indepdenent of any GUI
dependencies and doesn't use QStandardItemModel anymore but custom
items. This also allowed to minimize the API a bit and make it more
specific (a real rename function instead of some hidden way of using
setData).

I couldn't see any regressions and we do have a quite good unit-test for
it too. (it covers around 60% currently IIRC). 

It'll hopefully also make it easier to change the actual implementation
to a ref-counted version or something other. I'm not sure thats really
necessary though, it should be enough if places that do store
item-pointers also listen to model-signals to find out wether their item
is deleted and then remove it from their internal storage.

Andreas

-- 
You will obey or molten silver will be poured into your ears.