Use correct specialist sector tag type

The tag type for the content API tags call is "specialist_sector" not
"specialist_sectors"
Merge pull request #1271 from alphagov/fix-specialist-sector-api-call

Use correct specialist sector tag type
Allow extract text feature to be controlled by env var
Upgrade to Rails 3.2.17
Merge branch 'build-10760-hotfix'
Merge pull request #1269 from alphagov/extract-text-feature-controlled-by-env-var

Allow extract text feature to be controlled by env var
Register more formats with Panopticon

In addition to detailed guides, register consultations, document 
collections, policies, publications, and statistical data sets with 
Panopticon.
Set the correct slug in the RegisterableEdition

Use Whitehall's UrlMaker to build the correct slug for an edition,
including the /government prefix where appropriate.
Changing Panopticon to register all publications

Also removing redunant tests for specific content types
RegisterableEdition has Edition type or subtype

With Model's sometimes having a subtype (eg. Map or Policy Paper), RegisterableEdition.kind will return the Edition's correct type.
Use the global url_maker instead of a new one
Check value is enumerable before enumerating.
Merge pull request #1262 from alphagov/register-moar-formats-with-panopticon

Register moar formats with panopticon
Merge pull request #1274 from alphagov/fix_feed_filters

https://www.pivotaltracker.com/story/show/65971028

Fix 500 on feed request with string instead of array
Copy specialist sectors to new drafts
Fix indentation of welsh-language-scheme block
Add 'About our services' corporate info page
Merge pull request #1275 from alphagov/copy-specialist-sectors-to-new-drafts

Copy specialist sectors to new drafts

https://www.pivotaltracker.com/story/show/65361088
Add translations for new page
Merge pull request #1273 from alphagov/about-our-services-corporate-page

About our services corporate page