Allow the video player to work with links with redirection.

This PR provides possibility for the video player to work with different video formats and adds support of links with redirection (like, http://goo.gl/pxxZrg).

There is one issue I do not know how to resolve it right now:
`No playable video sources found.` does not show when at least one incorrect link with redirection exist.

**For testing:**
HTML5 links: 
https://s3.amazonaws.com/edx-course-videos/edx-intro/edX-FA12-cware-1_100.mp4
https://s3.amazonaws.com/edx-course-videos/edx-intro/edX-FA12-cware-1_100.webm
https://s3.amazonaws.com/edx-course-videos/edx-intro/edX-FA12-cware-1_100.ogv
Correct link with redirection: http://goo.gl/pxxZrg
Incorrect link with redirection: http://goo.gl/U4GXnN

@jmclaus , @auraz please review.