- getting the php set up for sprites

We now determine the class and title before the link then apply it to
the link so that we can sprite the link instead of feeding the images in
directly.
- css to deal with the sprite states

This deals with the sprite states for feature :active and when it's not
featured.
adding the core sprite image
- space on the featured column

This just gives the feature column some more breathing room on the date.
whitespace clean up
Drop references to BraveNewCode Piggy app

Per Dan, they have dropped the product
More Piggy(Mobile) Cleanup

Also remove from list-table.php (props Andrew), and pull translation
strings from pot file
Merge pull request #463 from 1bigidea/drop-mobile

Brave New Code has dropped Piggy (iOS/Android Web App)
Merge pull request #456 from curtismchale/feature/417-featured-ui-improvements

Feature/417 featured ui improvements
Merge branch 'master' of https://github.com/wp-e-commerce/WP-e-Commerce