Reload gravatar images in retina resolution if appropriate.
Reload gravatar images in retina resolution if appropriate.

This pairs up with the implementation of $.fn.retinaGravatar() in djblets to
actually do the reloads when appropriate.

Testing done:
Checked the gravatars for the "My account" image in the upper right hand of the
page and the user infobox.

Reviewed at http://reviews.reviewboard.org/r/3556/

bkochendorfer/reviewboard,1tush/reviewboard,bkochendorfer/reviewboard,KnowNo/reviewboard,custode/reviewboard,brennie/reviewboard,sgallagher/reviewboard,1tush/reviewboard,reviewboard/reviewboard,beol/reviewboard,davidt/reviewboard,custode/reviewboard,1tush/reviewboard,KnowNo/reviewboard,chipx86/reviewboard,reviewboard/reviewboard,beol/reviewboard,custode/reviewboard,reviewboard/reviewboard,beol/reviewboard,davidt/reviewboard,bkochendorfer/reviewboard,KnowNo/reviewboard,brennie/reviewboard,sgallagher/reviewboard,beol/reviewboard,sgallagher/reviewboard,bkochendorfer/reviewboard,1tush/reviewboard,chipx86/reviewboard,davidt/reviewboard,1tush/reviewboard,davidt/reviewboard,1tush/reviewboard,sgallagher/reviewboard,1tush/reviewboard,chipx86/reviewboard,1tush/reviewboard,chipx86/reviewboard,reviewboard/reviewboard,custode/reviewboard,brennie/reviewboard,brennie/reviewboard,KnowNo/reviewboard,1tush/reviewboard