OPEN - task 17: Editor/View 
http://github.com/markus1978/emf-fragments/issues/issue/17

A lot of small fixed to make first srcrepo examples with mongodb work.
Model now shows correctly within the editor.
The modisco content provider could not be used.
The modisco modelbrowser seems to load whole models, and I did not get
it to work.
OPEN - task 17: Editor/View 
http://github.com/markus1978/emf-fragments/issues/issue/17

Added an ItemProviderAdaptor that can be used as an base class for
generated provider classes. This adapter allows to visualize fragment
roots, attributes, and references. More feature could be added in the
future.

Added a test case for the persistence of extrinsic IDs.