Initial commit of updated signin page with dependency injection

NOT WORKING
Merge branch 'abstract-mq' of https://github.com/guardian/frontend
Add injection to dev build and tweak signin
Add dependencies for Identity
First draft of Identity scala API client
added account SVG and account button
Refactoring Scala ID API client in progress

Introduce client-specific Error type that can deal with API error
responses and http exceptions.

Split ID-specific API code from the general API interface.
updated account control spec to include rendering
jshint updates
Added basic fragment for the identity topnav
Merge remote-tracking branch 'origin/af-identity-signin-with-scala-client' into frj-signin-fragment
Add combined browser + os stats
Added a caption to the table
total views
total views for os, browser, and combined
Merge conflicts and added switch
Merge conflicts and added switch
Merge conflicts and added switch
Fixed routes and switches
Changed a few bits to get the account-nav controller working