Add finer support for documentation on dynamic metamodel
Add finer support for documentation on dynamic metamodel

The documentation is added to the Python class linked to an EClass
instance. This way, each time 'help' is called on a model element
instance, the right documentation is displayed. This documentation is
fetched from the '.ecore' metamodel, from one of the entry of
EAnnotations associated to the metaclass.

pyecore/pyecore,aranega/pyecore