Add RegisterableTravelAdviceEdition
Add observer to register editions with panopticon
Remove unnecessary loading of the countries list.
Stub out panopticon calls in other tests.
Bump govuk_content_models to get indexable_content
Split edition setup out into individual tests.

Makes it easier to setup different cases.
Use WebMock to assert panopticon registration

Gives us an integration test through the full app.
Add comment about observer
Prevent webmock from loading in dev mode
Merge remote branch 'origin/master' into panopticon_registration

Conflicts:
	Gemfile
	spec/controllers/admin/editions_controller_spec.rb
Merge remote branch 'origin/panopticon_registration'