* Update models: add MetadataMixin
* Fix name of model in Metadata API definition
* Add API endpoints
* Update API version
* Fix syntax
* Add API endpoint for RO, RO line, RO line extra item
* Add Metadata to Contacts
* Fix link in API version
* Fix name of model
* Fix error?
* Fix error?
* Fix all errors, hopefully..
* Add tests for order, line, extraline metadata
Extend for PO, SO
* Add tests for metadata for Company-related models
* Fix spelling
* Consolidate metadata test for all part models into one test
* Add test for all Stock metadata
* Update stock test_api
* Add all metadata tests for orders
* Fix various errors in tests
* Fix model name
* Add migration files
* Update tests for metadata
* Resolve conflict around API version number
* Rename migration file
* Rename migration file
* Will Contact edit endpoint work better?
* Revert changes in URL definitions
* Remove test, duplicate
* Fix tests with fixed PK, not from fixtures, to use a dynamic PK
* Fix migration overlap
