Add basic frontend assets with case-studies page

- Add IE specific stylesheets
- Add them to the pre-compile list in `config/initalizers/assets.rb`
- Add them to the application layout
Set-up slimmer correctly

- Use asset path for the assets to work in production
- Use Plek to locate static for slimmer
- Enable caching on slimmer in production
Create presenter for content_item

This will need to be split at some point in the not to distant future
into a case study presenter and a generic edition like presenter. But
for the moment it is in a generic content item presenter.

Also use components to make the page closer represent the direction it
is heading in.
Add basic styling for case study page
Add format names for heading context

Add in the en localizations of the different formats and use
format_display_type to create a context for the heading.
Move translation call to the view
Use Plek abstraction rather than an ENV variable
Add startup script

Runs government-frontend on the correct port. A convenience for local development.
Support UTF8 characters in URLs

After some discussions we agreed that URLs processed by content store
should always be in their 'encoded' form, ie. any special characters
should have been escaped.

The content store client libraries will actually raise an error if
invoked with a URL which is not encoded, because the urls are processed
using URI.parse.

Furthermore, rails will by default un-encode a URL received from an HTTP
request into a UTF8 string. Therefore we need to re-encode any
parameters derived from an HTTP request before making any api calls to
content store.

Reference:

https://trello.com/c/89N8zA8g/65-content-store-doesn-t-like-non-ascii-characters-in-paths
Merge pull request #5 from alphagov/add-startup-script

Add startup script
Merge pull request #4 from alphagov/new-frontend

Style case-study page
Merge pull request #6 from alphagov/support-utf8-characters-in-urls

Support utf8 characters in urls
Handle paths for translated content

Rails by default assumes anything after a full stop in a request path represents
the format of the request. We override the constraints in the routing to ensure
the entire request path makes it through to the controller.
Merge pull request #7 from alphagov/handle-translated-paths

Handle paths for translated content