Use ODI content models gem
We don't have Whitehall content
Update test to use a type that we actually have
Use govuk_content_models fork to get dynamic Artefact validator
Use content models from git, not local
Update content models to get fixed format list
Update tests to match our content types
Fix indexing test for new models
Update tests for new model types
Merge branch 'refs/heads/master' into feature-odi-content-models

Conflicts:
	Gemfile
	Gemfile.lock
Merge pull request #5 from theodi/feature-odi-content-models

Use ODI content models