Update index.html

I'm changing the video from youtube to the video from ted talks site. This video has more accurate closed captioning and also closed captioning for multiple languages. This is a requirement for all videos we have in the future to allow deaf people to access audio.
Update index.html

Added more changes to allow screen reader users to identify the video frame and also tab past the video. It appears that the video has better captions, but sighted keyboard-only users may have issues playing the video when tabbing through the page. (May have to address this issue later, since screen reader users can successfully play the video with no problem)
Update style.css

Added code for hidden skiplink. Skiplink will only become visible if keyboard users tab to it.
Update header.html

Added hidden skiplink at top of page (it should always be the first tab stop). Added skiplink target to the container div. May need to add JavaScript later to make sure this works in IE and Safari.
Merge pull request #23 from lamarjordanux/fix-accessibility

Fix accessibility