Launch Candidate Features

[thisandagain]

Tracking loose ends. Feel free to add items that you would want to see in a launch candidate:

• [ ] Re-enable login
• [ ] "Newest" discovery by locale
• [ ] App activity (remixes, views, etc) as per spec
• [ ] Allow (queue) sharing when user is offline

/cc @k88hudson @davidascher @vazquez

[thisandagain]

See discussion in https://github.com/mozilla/webmaker-app/issues/1035