Heartbeat: improve setting the errorstate, add ajaxurl to the settings object when loading on the front-end, some code cleanup, see #23216

git-svn-id: http://core.svn.wordpress.org/trunk@23882 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-alpha-23883.

git-svn-id: http://core.svn.wordpress.org/trunk@23883 1a063a9b-81f0-0310-95a4-ce76da25c4cd