Update Neo4j dependency
More work on virtual units.
 - set author on creation
 - allow fetching VUs for a given user
 - @Fetch the author by default
Add method for setting ref descriptions on virtual units.

Additional refactoring of REST API.
For consistency, allow setting description refs on top level VUs
Make creation of users/groups more consistent WRT members (also fixes #38)
Remove unnecessary exceptions from post-process signature
Make the creation post-process functor generic to avoid casting
Add auth set and vocab to holder types with child count cache
Fix frame method on vocab/auth sets which was causing a proxy error.
Merge branch 'master' into acl_graph

Conflicts:
	ehri-extension/src/main/java/eu/ehri/extension/CvocConceptResource.java
	ehri-extension/src/main/java/eu/ehri/extension/GroupResource.java
	ehri-extension/src/main/java/eu/ehri/extension/UserProfileResource.java
	ehri-extension/src/main/java/eu/ehri/extension/VirtualUnitResource.java