Twenty Fifteen: Fix missing commas in the stylesheet.

props iamtakashi.
fixes #30068.

git-svn-id: https://develop.svn.wordpress.org/trunk@29988 602fd350-edb4-49c9-b593-d223f7449a82
Script-loader: remove 'heartbeat' dependency for post.js and inline-edit-post.js, fix dependencies for autosave.js. Fixes #30008

git-svn-id: https://develop.svn.wordpress.org/trunk@29989 602fd350-edb4-49c9-b593-d223f7449a82