Ignore filter on non-list query.
Issue #150: Allow referenced resource to show only entity ID(s).
Issue #156: HEAD is a body-less GET.
Accept header negotiation for the output format.
Pass the wrapped entity to a callback method.
Merge pull request #166 from Gizra/callback-fix

Pass the wrapped entity to a callback method
Fix \RestfulEntityBase::getImageUris to work also for multiple value images
Make user resource optional.
Plugify the CSRF token response.
More verbose file upload.
Remove count for non get requests in Hal-Json.
Allow specifying more options per endpoint (e.g. access callback).