Draft of serializers, not to lose the progress in case of emergency,
will rebase before merge into the master. Currently complex structures
don't work right.
AbstractSerializer rewrite.
Adds getCreatedBy method for Comment model.
Handles null object case in getField method of AbstractSerializer.
Replaces old serializers with new on users route.
Replaces old serializers with new on posts route.
Fixes typo.
Implements missing getMedia method of attachment model.
Replaces old serializers with new on comments route.
Replaces old serializers with new on auth route.
Replaces old serializers with new on session route.
Replaces old serializers with new on stats route.
Replaces old serializers with new on search route.
Replaces old serializers with new on time-line route.
Replaces old serializers with new in pubsub.
Removes redundant toJSON from models.
Replaces old serializers with new in tag synchronizer.
Adds info to anonymous.
Adds attachment serializer.
Post serializer strategy refactoring.