Fix various i18n issues on the dashboard. Limits it to posts and pages only for 3.8.

props SergeyBiryukov, dimadin.
fixes #26066.


git-svn-id: https://develop.svn.wordpress.org/trunk@26704 602fd350-edb4-49c9-b593-d223f7449a82
Unit Tests: Avoid using mime_content_type() as it fails miserably in PHP 5.2.

props bpetty.
fixes #26155.


git-svn-id: https://develop.svn.wordpress.org/trunk@26705 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fourteen: Wait for DOM ready in the customizer, which was breaking IE8.

props ocean90.
fixes #26445.


git-svn-id: https://develop.svn.wordpress.org/trunk@26706 602fd350-edb4-49c9-b593-d223f7449a82
Remove redundant closure for such a simple file. see #26445.


git-svn-id: https://develop.svn.wordpress.org/trunk@26707 602fd350-edb4-49c9-b593-d223f7449a82