Add feedback link

To improve the product for users, we need feedback.
This adds a feedback link in place of the updated date and moves
the updated date to sit with the departmental meta data.
Updating tests

Tests updated to reflect changes to mark up after adding feedback link.
As the last updated date is now moved into the description list metadata
we no longer need to test for presence of a colon as its added automatically
via CSS. Thanks for your help with this @tommyp
Merge pull request #107 from alphagov/add-feedback-link

Add feedback link
Make section_id values consistent
Better title tags for sections and update pages

Currently, every page in a manual has "Manual Title - GOV.UK" for the title
tag. This isn't very helpful if you had multiple pages within a manual open at
once.

This change prepends the section ID for HMRC Manuals, the section title for
non-HMRC manuals or the word "Updates" for update pages.
Upgrade to Ruby 2.1.4

This app and cma-crawlers are the only things using 2.0.0-p451 on GOV.UK. If we
upgrade them, we can drop support for that Ruby version.
Merge pull request #109 from alphagov/upgrade_to_ruby_2-1-4

Upgrade to Ruby 2.1.4
Merge pull request #108 from alphagov/better_title_tags

Better title tags