* lint amnesty in teams,tests,survey and verify_student

* Hide private team-sets from users not on a team

* Modify add team count to factor in team visibility

* Fix bug that broke search w/in private team-sets

* correctly resolve teamset-level and course-level max_team_size

This will remove imports from __future__ that are no longer needed.

https://docs.python.org/3.5/library/2to3.html#2to3fixer-future

* no student change to instructor managed team

* Address comments & fix unit tests

* fix jenkins test failure

* Fix eslint errors

* Fix xss warnings

* Fix bokchoy test

 This is needed so Masters learners will not be in the same team as verfied and audit learners. If the team is designated as organization protected, it will not be visible or accessible by verified or audit track learners
MST-34

* For all files, from __future__ import unicode_literals.
* Add @python_2_unicode_compatible to both models.
* Test six.string_type(obj) for both models.

Also, fix some new pylint warnings and improve model repr methods.

MST-24

MST-6

ARCH-482

Please note that this is a squshed commit and the work of:
Symbolist, macdiesel, nedbat, doctoryes, muzaffaryousaf and muhammad-ammar

Also remove useless docstrings where they were added to keep pylint
quiet.

* Upgrade edx-submissions
* Upgrade edx-ora2
* Upgrade edx-val
* Upgrade edx-proctoring
* Update all edx-platform code that depends on DRF, including:
  - auth_exchange
  - cors_csrf
  - embargo
  - enrollment
  - util
  - commerce
  - course_structure
  - discussion_api
  - mobile_api
  - notifier_api
  - teams
  - credit
  - profile_images
  - user_api
  - lib/api (OAuth2 and pagination)

* Upgrade edx-submissions
* Upgrade edx-ora2
* Upgrade edx-val
* Upgrade edx-proctoring
* Update all edx-platform code that depends on DRF, including:
  - auth_exchange
  - cors_csrf
  - embargo
  - enrollment
  - util
  - commerce
  - course_structure
  - discussion_api
  - mobile_api
  - notifier_api
  - teams
  - credit
  - profile_images
  - user_api
  - lib/api (OAuth2 and pagination)

TNL-3281

TNL-3202

TNL-3172

TNL-3112 TNL-3154

TNL-3012

TNL-3068

Create read-only serializer to handle User/UserProfile data
together.

Refactor GET accounts to use the new read-only joint serializer

Fix tests to check for new expanded user info

Update tests in teams/tests/test_views.py to test for both
public and private profiles on expands user

Update serializer to utilize the request object for creating absolute uris

TNL-1911

TNL-2892

TNL-1898

Also adds a generic paginated list view and Teams list view. The
common PaginatedView takes a collection and a view class for its items
and creates a header and footer with correct pagination. The topics
list view is refactored to use this generic view.

Authors:
  - Peter Fogg <pfogg@edx.org>
  - Daniel Friedman <dfriedman58@gmail.com>