case study can be associated to world location and orgs
include the tests on case studies

should_allow_association_with_worldwide_organisations
should_allow_association_between_world_locations_and

Conflicts:
	test/functional/admin/case_studies_controller_test.rb
Merge pull request #325 from alphagov/case-study-locations

Associate case studies with Worldwide locations and organisations

https://www.pivotaltracker.com/story/show/45308927