upgraded laravel version from 5.0 to 5.2.
Changed ORM from eloquent to Doctrine to support better inheritance handling
basically eloquent does not suppor the inheritance model used by Silverstripe
which makes dificult to implement write apis on model hierarchies defined with
SS schema.
Refactoring.
Change-Id: I802e171c8b95e81dc21578543ddb6a02003985e5