Post format retina icons for both color themes, props melchoyce, aaroncampbell. See #24290, see #24331.

git-svn-id: http://core.svn.wordpress.org/trunk@24294 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-beta3-24295.

git-svn-id: http://core.svn.wordpress.org/trunk@24295 1a063a9b-81f0-0310-95a4-ce76da25c4cd