make the generated SSB's retina-enabled

Fix from: http://www.hongkiat.com/blog/mbp-retina-blurry-text/ and http://apple.stackexchange.com/questions/69038/open-in-low-resolution-checkbox-on-retina-macbook-pro-checked-and-disabled

Tested on 10.8.5 with Chrome Version 29.0.1547.76.