fcr:batch should return 400 Bad Request when no children exist or none of the specified children exist
adds access roles API to fcrepo-webapp REST API
adds access roles UI to node pages
adds an RDF pointer to the access roles endpoint

Resolves: https://www.pivotaltracker.com/story/show/62019902

made enum fields private
removed unneeded roles provider from AccessRolesResources
fixes camel case fcr:accessRoles endpoint, making it fcr:accessroles
Merge pull request #206 from futures/BadBatches

fcr:batch should return 400 Bad Request when no children exist or none of the specified children exist
adds access roles API to fcrepo-webapp REST API
adds access roles UI to node pages
adds an RDF pointer to the access roles endpoint
made enum fields private
removed unneeded roles provider from AccessRolesResources
migrated org.fcrepo.auth to org.fcrepo.auth.common to match project name
sends bad request instead of 500 for bad JSON data
cleaned up some warnings