Update topic trees

Test Plan:
- None
Update youtube api files

Test Plan:
- None
Disable youtube player support until a workaround for the api bug is found.

I'd rather not do backouts for this work because there's a lot of good
video refactoring that happended to support multiple players.

Test Plan:
- None
Disable functionality if the APIs aren't available

This is in preparation for getting on the desktop ap store and android
store.

Test Plan:
- Make sure items are gone in desktop browser for downloading and
  sharing
Remove npm install jsx command

Latest `jsx` is included in `react-tools` and `npm install -g jsx` installs an older version, so I removed the latter.
Merge pull request #50 from farezv/patch-1

Remove npm install jsx command
Only use Storage support on fxos devices even if desktop has pref on.  Fixes #49

Desktop's implementation is bad and hangs.
See bug 1106676

Test Plan:
- Make sure app loads instead of hanging when device.storage.enabled is
  explicitly set to true
Add support for Bengali (locale: bn)
Update topic trees and include new Bengali topic tree
Update scripts to generate Bengali topic tree

Test Plan:
- None
Fix add bn to support locales in Util

Test Plan:
- Load app, open console, make sure it loads the right topic tree
Merge branch 'master' of https://github.com/bbondy/khan-academy-fxos