Replaces images with a 2x version

On retina computers, the normal images look awful. Because of this all images (all two...) have been replaced with an image twice the size. This also replaces the old method for making images black/white, with a new sprite method that has better browser support (Firefox!).

Later on, only retina users should get the 2x version, so that the page load is only heavier for the ones that need it.
The hover effect on the 'social wells' now use plain CSS instead of CSS+javascript. The old way of doing it was silly
Refactoring
Changed the way buttons on the front cards are shown. The old way was silly.