Added idservice module, with tests, in preparation of building automatic id assi
gnment to inventory models. refers to #83
Added automatic ID creation for Collection, Project, and Item.  This requires an ID service to mint and bind IDs.  Added new access_loc field for each model to store the target url, which is passed to the ID service. Thus, there is a new schemamigration. Also added test for auto ID. Closes #83
Removed redundant default behavior for Collection "created" field
Replaced IDService interface with IDService class that is tied to GW's idservice platform
Moved idservice calls in model save() methods to separate function
Moved mintandbind() method out of the models module and into the idservice module
Merge pull request #84 from gwu-libraries/idcreation

Idcreation
Merge branch 'master' into inventory-import-tests
Also edited tests by adding tearDown() function to import testing class, as well as PEP8 style changes

Conflicts:
	inv/invapp/tests.py