bumped to v0.8.4
fixes #504 Social login does not return the serialized user object, just its RID
fixes #506 GET /users?fields=user.name returns error 500
Social Mock Service refactoring...
Better management of some users' attributes

The id of social networks now are in the visiblyByRegisteredUsers._social data structure
The data collected from the social networks are stored in the visibleByTheUser field