Add HTTP_HOST to environ variables mocked. Also add license headers to run.py.

Added logic for every GHOP specific model. Defined logic for every model defined for GHOP. These logics do nothing special now. They are just inherited from their parent classes. Necessary GHOP specific logic will be added later as necessary. Reviewed by: Lennard de Rijk

Added licenses and fixed the authors of __init__.py for the GHOP module.

Changed imports in models to comply with recent GHOP code move. Reviewed by: Lennard de Rijk