Show world office summary and description on admin show page
Associate worldwide offices with sponsoring organisations
Admin interface for associating worldwide offices with organisations
Allow WorldwideOffices to be associated with WorldLocations
WorldwideOffices now have a main contact

Defaults to the first contact, but can be overridden in admin
Tidy up admin contact-related partials

Using more idiomatic Rails collection rendering.
Bugfix: render properly if no addresses
Fix test

The button only appears if the contact is not already 'main', so we have
to change the order of this test a little.
Add services to wordwide offices