In 2.0.0 the generated factory code becomes useless or could be simplified

[opcoach]

With the new GMAFactoryImpl class, the EMF factory is correctly generated with the right names of the developper structure.

The overridden factory code is useless and could be reduced to a simple inheritance code.
On the other hand, the generated extension (factory_override) becomes also useless.

[opcoach]

Fixed with 5076ae9