Fleshing out virtual collections.

 - add script to create VC content type
 - add VC fixtures
 - add tests for current functionality
Fix display of scopes in permission error
Make virtual collections require a unique id
Add, via the awesome power of copy-and-paste, a VC resource and client test
Merge branch 'master' into virtual_collections
Merge branch 'master' into virtual_collections
Actually we don't need to re-index after adding this node
Merge branch 'master' into virtual_collections
Merge branch 'master' into virtual_collections
dans ead import test, no actual dans-importer needed
multilingual worked only for the toplevel, because of permissionscope. with a hack it now works for lower items as well
admin-district added as test
changed dansead and niodead property files to better adhere to the allowedNodeProperties
my previous hack to have 'everything ending with Access' be treated as an AccessPoint violates conditionsOOfAccess, so the hack is now to treat everything ending with AccessPoint as an AccessPoint
Merge branch 'master' into virtual_collections
Rename VirtualCollection to VirtualUnit to reflect its relationshio to DocumentaryUnit
Tweak fixtures to reflect new structure.
VirtualUnit is not a described entity
a prefLabel does not need to have a xml:lang attr. if not, it will be the prefLabel for all languages for which no prefLabel is given
Don't log so heavily loading fixtures