adds tests for listing endpoints on agent controllers
improve position reordering test by exercising the shuffling code
added tests for external id controller
added test for list endpoint, and removed defunct tree update endpoint  on digital object controller
removed obselete methods from resource model
tidied formating
removed obselete 'children' endpoint from resource controller
added test for creating a repository to the repository controller
bringing user controller to 100% coverage
a spec for location controller to fill a couple of gaps in coverage
added a test for gappy ids, and tidied a bit
added test for location validation
removed unnecessary checks in collection management linked records validation
added tests for linked records in collection management controller
fixed cut and paste error
uncommented test for a non-array given to linked records
fixed reference to class method generate_title
added a test for the delete feed on the update feed controller
removed obselete 'link' method on digital object model, and tidied test
added some tests for corners of ASModel not touched by other tests