Update MediaElement.js to include i18n fixes that were accepted upstream. Add strings to script-loader.

props SergeyBiryukov.
see #24183.



git-svn-id: http://core.svn.wordpress.org/trunk@24755 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/danielklotz/WordPress-Local-Beer-Site