Add in youtube api lib

Test Plan:
 - None
Set developer name to Khan Academy away from Brian Bondy

Test Plan:
- None
Add support for using the YouTube player

Test Plan:
- Test everything relating to videos
Add missing dependency for youtube api

Test Plan:
- None
Add support for loading indicator while video is loading

Test Plan:
- None
Merge branch 'master' of https://github.com/bbondy/khan-academy-fxos