Dashboard backwards compatibility updates.
 * Restore missing wp_dashboard_rss_control() helper.
 * Restore all original 3.7 functions, deprecating many, reusing others. 
 * Rename and remove functions so as not to clash with the original dash plugin.
 * Filter cleanup/restoration.

see #25824, #26334.


git-svn-id: https://develop.svn.wordpress.org/trunk@26690 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fourteen: fix too-wide search "jump to" link and provide focus on the search input when it's used. Closes #25592.

git-svn-id: https://develop.svn.wordpress.org/trunk@26691 602fd350-edb4-49c9-b593-d223f7449a82
Deactivate MP6 on update to 3.8.

If left on, it introduces a lot of weird issues not easily diagnosed. MP6 will be updated before release to prevent itself from functioning 3.8+, but this will cut down on support requests by people who update core but not MP6, which was a fairly popular plugin.

fixes #26334.


git-svn-id: https://develop.svn.wordpress.org/trunk@26692 602fd350-edb4-49c9-b593-d223f7449a82