Merge pull request #5 from mikesname/master

Remove old plugin code and cleanup REST methods.
cleaned ehri-extension pom.xml
Added relatedBy for a concept
removed depthFilter from VocabularyResource and CvocConceptResource
adedd a TransactionEventHandler to track changes in the graph
commented out the registration of the transaction handler
updated the README
Allow initial groups to be set when creating users
Allow listing members of a group from the REST API, i.e. /group/{groupId}/list
Added options to ListEntities top produxece json or xml output
Merge branch 'master' of https://github.com/PaulBoon/neo4j-ehri-plugin
into merge_paul. Fixed a few conflicts in tests.

Conflicts:
	ehri-extension/pom.xml
	ehri-extension/src/test/java/eu/ehri/extension/test/UserProfileRestClientTest.java
Rename bundle toString method as toJson (we are going to add a toXml one as well.)
Add a facility to output the node bundle as XML.

This uses a rather ad-hoc schema and still needs some work to output
properties with the correct type.
Improvise XML serialisation of array values.
Doc cleanup
Doc cleanup
Add XML options to vertex serializer
Use new XML serializers for listing items