OPEN - task 18: Datastore registry 
http://github.com/markus1978/emf-fragments/issues/issue/18

Created edit/editor projects. But those wont work jet.
In preparation refactored `FragmentedModel` to a `ResourceImpl`.
OPEN - task 18: Datastore registry 
http://github.com/markus1978/emf-fragments/issues/issue/18

`FragmentedModel` is now a regular resource that can be instantiated
with only a URI. The only defaultly registered data store is the in
memory data store. Other datastores have to be added via
`DataStore.registry`.
OPEN - task 18: Datastore registry 
http://github.com/markus1978/emf-fragments/issues/issue/18

Fragmented models are now saved via the regular `Resources` interface.
Added a proper `ResourceSet` implementation.
OPEN - task 18: Datastore registry 
http://github.com/markus1978/emf-fragments/issues/issue/18

Changed example for recent api changes.