Preserve alpha in WP_Image_Editor_GD when images are not resized.

Props joehoyle
see #23039


git-svn-id: http://core.svn.wordpress.org/trunk@23884 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Revisions: remove the new _wp_last_revision_matches_current_post(), can be replaced by a simple revisions version check. Fixes #23913

git-svn-id: http://core.svn.wordpress.org/trunk@23885 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Autosave: use heartbeat to determine when connection is lost and disable the Save and Publish buttons. Re-enable the buttons when connection is restored. Props dh-shredder, see #23220

git-svn-id: http://core.svn.wordpress.org/trunk@23886 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-alpha-23887.

git-svn-id: http://core.svn.wordpress.org/trunk@23887 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Pass the tag object instead of just the tag ID to topic_count_text_callback. see [23741]. see #21198.



git-svn-id: http://core.svn.wordpress.org/trunk@23888 1a063a9b-81f0-0310-95a4-ce76da25c4cd
No need to check for the presence of a current user in a privileged ajax action. see #23665.



git-svn-id: http://core.svn.wordpress.org/trunk@23889 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Replace $user_id removed in [23889] with a direct function call. see #23665.



git-svn-id: http://core.svn.wordpress.org/trunk@23890 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Merge branch 'master' into fix_23901