Remove the feedback button if the screen width is small. Otherwise, it obscures a large part of the screen on a mobile device.
Add username validity checks into Javascript

The duplicate check is not included in the Javascript.
Python checks are still in place, but should not be hit, just as a double check.
Fix NPM error in installation script.
Tests for Javascript checks of username validity
Admins and moderators should be able to see all public explorations in the Contribute gallery.
Grant moderators delete permissions for explorations; record roles when deleting.
Add more tests for editing and deletion rights of different users
Introduce the concept of beta explorations, and allow them to be publicized or unpublicized by moderators. Fix an error in the admin/moderator permissions.
Merge branch 'master' of https://code.google.com/p/oppia
Amend test of editing and deleting permissions
Amend tests for user editing and deleting permissions
Add callback function for initial MIDI library load, otherwise a console error is raised.
Add explanation of how beta mode works.
Minor edits to explanations of how beta mode works
Merge branch 'master' of https://code.google.com/p/oppia
By default, hide beta explorations in both galleries.
Merge branch 'master' of https://code.google.com/p/oppia
Allow an announcement to be placed in the contribute gallery.
Basic functionality for moderators to get users' email addresses
Merging moderator page into main branch

Merge branch 'master' of https://code.google.com/p/oppia