Move SpecialistDocumentEdition over from content models

Remove outdated extensions file.
Remove unused code from SpecialistDocumentEdition

Most of this was a hang over from original Edition?
Fix for ManualDocuments Preview not working

We were missing an action which wasn't needed until some previous
refactoring changed how the Preview worked. I've added some tests to
make sure this doesn't happen again along with adding a service for
previewing manual documents.
Merge pull request #109 from alphagov/fix-manual-document-previewing

Fix for ManualDocuments Preview not working
CMA case form object
Remove CMA-specific fields from SpecialistDocument

This is done by extracting CMA case object.
Remove CMA import scripts
Pull in specialist_document_edition factory from content_models

Merge all factory definitions into a single FactoryGirl.define block.
Remove CMA-specific params from manual document builder
Merge pull request #108 from alphagov/refactor-cma-cases

Specialist documents and CMA case refactor
Remove unused code as reported by SimpleCov
Merge pull request #110 from alphagov/remove-unused-code

Remove unused code as reported by SimpleCov
Change notes for manual sections
Merge pull request #112 from alphagov/change-notes

Change notes for manual sections
Manual must publish its documents everytime
Merge pull request #113 from alphagov/fix-add-section-after-initial-publish

Manual must publish its documents everytime
Use govuk_admin_template

- Add gem to gemfile
- Include stylesheet in base.css
- Rewrite application.html.erb to use template
Alignment and spacing tweaks

Applied as per styleguide
Disable Rubocop IfUnlessModifier
Add Rubocop to CI test run