add Location header to all JSON-API create actions

Conform to the specs, "The response MUST include a Location header identifying the location of the primary resource created by the request."
http://jsonapi.org/format/#crud-creating-responses-201
rename uri_name model to owner_name
rename user_groups display_name field to name (preserves index) and re-add display_name
use group name for building uri attributes and add owner_uniq_name to nameable module

Owner_uniq_name avoids clash with name attribute on user_groups
Merge pull request #117 from camallen/spec_project_destroy_action

add Location header to all JSON-API create actions
Merge remote-tracking branch 'cam/rename_uri_name_model' pull request

Conflicts:
	spec/controllers/api/v1/groups_controller_spec.rb