ziafazal/SOL-493: Fetch scores via ScoresClient

Merge release into master

fixing issue with student re-verification.

Allow user partition version >= current version.

ECOM-2106

Hiding find courses button from dashboard of edge.edx.org
FYI @wedaly 

ECOM-1996

Fixing flaky TeamPageTest bokchoy tests

Release 2015 08 18 conflict

If code is deployed that updates the user partition version,
then the code is rolled back, we may see user partition versions
greater than the currently deployed version.

The previous behavior was to raise a TypeError when this occurred;
the new behavior assumes that the newer version is backwards
compatible and tries to load the partition.

The flaky test problems we've been seeing here are coming from not
waiting long enough after performing actions. By forcing
is_browser_on_page checks to wait until the page is fully loaded
instead of just looking for the presence of a single element, we
ensure that there will not be issues interacting with non-loaded
elements.

TNL-3069

Add sorting by last_activity_at.

Add USD labels to prices on track selection pages

Teams page content padding

Upgrade Django to 1.4.22

Updating documentation for team_membership endpoint

ECOM-2114

TNL-3011

Add sorting by team_count, as well as secondary sort (by name).

Recent changes to the team_membership API endpoint added the
course_id optional parameter, but the in-code documentation
was never updated to reflect this. The wiki documentation at
https://openedx.atlassian.net/wiki/display/TNL/Team+API is OK.

Related: https://github.com/edx/edx-platform/pull/9289

Release 2015 08 18 conflict

TNL-3071

This reverts commit cea274dc, reversing
changes made to 02cf9cac.

Only let global staff (is_staff=True) see the Proctoring tab in the Instructor Dashboard if the feature flag is enabled.

By doing this, we can prevent the bug where multiple users can join
a team simutaneously and push its enrollment over the defined
maximum value. Tests have also been added to confirm this behavior.

TNL-3061

Specify course key when retrieving credit requirements.

The 1.4.22 security fix makes it so that empty sessions are not written.
To keep the tests working, we now log in the user, so that some data is
saved to the session.

Use 0.1.3 of i18ntools

TNL-3012

Adding django admin command to create mongodb indexes

Change default donation amount to $10.

Merge pull request #9371 from edx/tasawer/story/ecom-1956-updte-validation-message-on-registration-page

Updating validation error message on signup page.

using ScoresClient instead of StudentModule

using ScoresClient without FieldDataCache

ECOM-2113

ECOM-1956

Clean up the Django ORM usage a bit