Implements rol.equals() to enable storing rol's instance in set and collections, and rol.is(Roles) to avoid comparing enums name ad clases members.
Removes roles enum mapping as user will save roles in db as Rol class and not a roles enum instances.
Deletes unused imports.
Merge pull request #6 from mbmihura/fbSdkAuthentication

Implements rol.equals() and rol.is(Roles)