Add loading indicator

So that a user knows something is happening display a loading indicator
while the Ajax request is performed.

Add `aria-busy` to let screen readers know something is happening.
Improve narrow tablet screen styles

- Removing the A-Z title for narrow tablet sized screens mean long words
  won't be longer than the column they have to be displayed in.
- Increasing the minimum height for narrow screens means the subsection
  border and background will always overlap the whole of the root list
Add IE specific stylesheets

This lets them get desktop styles rather than mobile stylesheets. Also
add in IE specific varables for JavaScript incase they are needed in the
future.

Add the new stylesheets to the precompile so they are on production.
Merge pull request #27 from alphagov/ie-fixes

Add IE specific stylesheets
Merge pull request #25 from alphagov/tablet-fixes

Improve narrow tablet screen styles
Merge pull request #23 from alphagov/loading-indicator

Add loading indicator
Update breadcrumbs on navigation

When you enter a subsection add the section to the breadcrumb trail.
When you leave the subsecion remove the breadcrumb.
Merge pull request #26 from alphagov/update-breadcrumbs

Update breadcrumbs on navigation
Show section descriptions in section lists

- Update mustache to conditionally show descriptions
- Update section and subsection pages to show descriptions
- Update styles for descriptions
- Update navigate to use `currentTarget` rather than `target`.
  `currentTarget` will contain the element that jQuery is attaching the
  event to rather than the element within the link which was acutally
  clicked.
- Update `getTitle` to get the title out of a list item regardless of if
  it is in a heading in the list item or the list item is the title.
Merge pull request #21 from alphagov/section-descriptions

Show section descriptions in section lists
Add JavaScript accidentally removed in 71b93b2c
Merge pull request #28 from alphagov/add-javascript

Add JavaScript accidentally removed in 71b93b2c
Register browse routes on deploy

Run the router:register_browse task as part of the router:register task
which gets called automatically on deploy.
Register redirects for browse pages at root on deploy

These will eventually be added to router-data and removed from here, 
but to make the deployment simpler, we're going to enforce these as 
part of Collection's route registration for now.
Merge pull request #29 from alphagov/register-browse-route-on-deploy

Register browse routes on deploy
Register redirects as exact routes

The existing redirects are 'exact' routes, so they override the prefix 
routes here. 

There isn't a good reason for these to be prefixes, so change them to 
'exact'.
Merge pull request #30 from alphagov/register-exact-redirects

Register redirects as "exact" routes
Use the section to generate the breadcrumb url

The subsection rightly contains the current section not a slug like this
was assuming. Make it use the section from the state to generate the
url.
Merge pull request #31 from alphagov/fix-breadcrumbs

Use the section to generate the breadcrumb url
Bump gds-api-adapters to 14.1.0

This includes a test helper for rummager that we need for testing the
call to get sectors associated with an organisation's content.