Remove unused image assets
Remove some more unused image assets
Add redrawn and hi-res step icons
Add redrawn information icon
Add Sass mixin for device-pixel-ratio media query
Add CSS rules for hi-res icons
Add hi-res information icon
Fix table caption padding in IE7

IE7 (and probably 6) ignore margins on table captions.
Move device-pixels import to application.scss
Add hi-res ordered list item icons

Add icons for up to 14 steps.
Change colours to match new greys.
Remove beta logo images
Add hi-dpi icons for high density screens

Also make naming consistent across icons.
Update colours to match new greys in appropriate icons.
Optimise icon assets
Add hi-dpi version of the footer crest

Also update colour to match new greys
Add device pixels mixin
Interpolate variable so it renders as a fraction

Opera only accepts device-pixel-ratio values as fractions
Add an .important class for links requiring an icon

Set the background-image of links with this class to the 'important'
icon.

Also fix up spacing of braces.
Fix indentation
Merge pull request #155 from alphagov/fix_ie_table_caption

Fix table caption padding in IE7
Bump the sizes of h2s & h3s 

So they stand out from body text

See Zendesk ticket https://govuk.zendesk.com/agent/#/tickets/14366