Merge branch 'develop'
Merge branch 'develop'
Don't display the responsive version during A/B testing.

It's too hard to control which version to display when we're caching out
files to the filesystem and serving them directly from the webserver.
Add google analytics A/B test code.

We'll be testing the responsive design.
Merge branch 'basic-responsive-styles'
Merge branch 'a_b_test_responsive_theme'
Merge branch 'develop'
Test swapping styles dynamically

Render the ms-header element in the responsive version
Merge branch 'a_b_test_responsive_theme'
Remove A/B testing code.
Merge branch 'remove_a_b_testing'
Restore responsive styling for cached attachments.
Don't use stylesheet link tags

We don't want timestamped assets here when the files are cached - we
want to reference whatever the latest stylesheets are.
Add viewport to attachment header for mobile devices.
Merge branch 'develop'
Add background colour to link-to-this annotation

White icon was nearly invisible against the off-white background.
Removing fixed-width font for responses

Fixes #151
Set background colours on the correspondence.

Closes #155.
Use retina version of main logo for large retina screens.
Merge branch 'issues/155-reinstate-colour-coded-correspondence'