Update govuk_admin_template to 1.1.2

* Update jQuery to 1.11.1
* Update Bootstrap to 3.2
Add link-open hook to API user table filter

When filtering the table, if a user hits ‘Enter’ it will open the first
link marked with a `js-open-on-submit` class
Merge pull request #264 from alphagov/update-admin-gem

Update govuk_admin_template to 1.1.2