Refactor and cache user info into user model

This is instead of fetching the info on each profile view.

Test Plan:
- Load user profile, make sure it loads
Don't fetch secrets.json file when the info is already avail from local storage

Test Plan:
- Make sure when info is avail in local storage it works fine.
- Make sure when info is not in local storage it works fine.
New minimized topic tree files with null mp4 videos rmeoved

Test Plan:
- Make sure a known null video no longer appears in topic tree when app
  is launched.
Code to remove and report on null mp4 url videos

Test Plan:
- Run script, spot check against untouched returned topic tree data
Add a contributors section to the README

Test Plan:
- None
Store user data files context sensitive to the current user

Test Plan:
- Make sure freshing doens't always say refreshing user info from server
  each time.
Convert # links to javascript:void operator

Test Plan:
- None
Don't use APIClient directly from main view to log out, use model instead

Test Plan:
- None
User specific info should clear when logged off and not redownload when using different users.

Test Plan:
- Test swatpping between 2 users. Make sure the console messages
  indicate what's goin on with regards to which info is being retrieved..
Add some basic info to the README

Test Plan:
- None
Added react-tools and jsx requirements
Merge pull request #1 from farezv/docs

Added react-tools and jsx requirements
Update UserInfo to have points earned during session

Test Plan:
- Watch a video, make sure user profile shows 750 more points than it
  used to
Fix energy points animation which was accidentally also updating profile
points

Test Plan:
- Watch video as points are increasing, switch to video. Make sure
  points display on profile doesn't say X of 750.
Fixup point progress.

Test Plan:
- Watch a video from start until end.
Add in Portugues translations

Test Plan:
- Load app with language set to portugues
Disable context menu globally

Fxos 2.2 has some default actions for long press like open in new tab
which doesn't make sense.  This disables contextmenus for now until
better support is added.

Test Plan:
- Start 2.2 simulator, do a long press. Make sure it doesn't do
  anything.