The key requirements of accessible media rendering are having
synchronized closed captions (taken from the media resource or
provided by an external SRT file) and a synchronized additional
audio description layer. videoJS offers these functionality by
using plain HTML5 features and Flowplayer is used as fallback
to deliver the content with a Flash application. Editors can
then chose in the media content element which strategy of
content delivery to use.

These changes are a result of the BLE project and are taken from
git://git.typo3.org/TYPO3v4/Incubator.git project-accessibility

Change-Id: I00990ca18e2d9743a67a2d248ff23a2cf2ee8b12
Resolves: #31770
Releases: 4.7
Reviewed-on: http://review.typo3.org/6639
Reviewed-by: Oliver Hader
Tested-by: Oliver Hader
Reviewed-by: Steffen Ritter
Tested-by: Steffen Ritter