Remove section column from tables

Research showed that the column wasn’t used when browsing publication
tables. It’s a wide column that clutters the view.
Add read-only section to metadata tab

Section has been removed from the browse table, but should remain
available within Publisher.

It looks like the intention was to include section but it isn’t
currently working. Explicitly add it back in.
Link publication title to edit view

Create a larger hit point in the area users are focusing on when
browsing the table of publications.

* Link to the locked edit view when a publication is published
* Link the sibling draft message too
Remove slug column

The slug is useful information when alongside the title, although that
information isn’t used to scan the table for a document to work on.

* Move the slug beneath the title so they can be directly compared
* Remove the wide slug column to improve table legibility
* Link the slug to the published version or the preview, depending on
state
Make the publication title more prominent

Titles are the main differentiator of publications and are used the
most when scanning the table.

* Make the title larger and more legible
Tidy up display of editions

* Use #X notation for brevity.
* Match colour of slug link
Make dates user friendly

* Use human readable date formats that match our style guide
* Shorten columns to show only the date, put provide the full date as a
title attribute if the user needs to check
Remove action columns and icons

The edit view can be consistently reached via the link on the
publication title. The preview can be reached via the link on the
publication slug.

* Remove the 2-4 columns for edit, preview, locked view
* Keep an actions column when a new edition can be created from a
published or archived edition. Shorten button text.
Add missing require.

We're getting occasional 'uninitialized constant' errors for
RegisterableEdition in this file.
Merge pull request #269 from alphagov/add_missing_require

Add missing require.
Merge pull request #268 from alphagov/better-docs-tables

Improve table of publications design
Update admin gem to 1.1.6

* Fix GillSans font stack
Merge pull request #272 from alphagov/bump-admin-gem

Update admin gem to 1.1.6
Add fields for public change note

* Use similar copy to the change note in Whitehall
* Avoid specifying whether something is major or minor, what matters is
whether the public should be notified or not.
* Avoid explaining the situations that the public should be notified
for now. Content team will decide this and will likely apply their
rules consistently without guidance.
* A list of places showing where the public change note will appear may
be useful, not currently included

This is based on the inset form elements pattern within GOV.UK elements:
http://govuk-elements.herokuapp.com/#guide-forms