Upgrade admin gem to 1.1.6

* Fix asset pipeline in Rails 4
* Upgrade Bootstrap to 3.2
* Upgrade jQuery to 1.11.1

https://github.com/alphagov/govuk_admin_template/blob/master/CHANGELOG.m
d
Remove styles breaking main navigation

* Generic header styles were adding margins and padding to the primary
navigation
* Remove unused styles, replace header styles with an admin gem title
class
Give the app a title
Match sign out text used in other apps
Cleanup Bootstrap tables

* Add missing thead and tbody elements to table
* Add a missing header for delete column on best and worst bets
* Add table-header style to give headers contrast
Cleanup main index view and buttons

* Align two action buttons horizontally and vertically space
Merge pull request #19 from alphagov/upgrade-admin-template

Upgrade admin gem to 1.1.6 and cleanup templates