CohortMembership Transaction Fixes

Fixes TNL-363: EdX OpenID provider doesn't handle unicode e-mails

jia/MA-1748 patch read states for users

Enforce order on these events to solve flaky condition.

Upgrade pip to 7.1.2

Audit logs were causing open_id provider logins to fail when
username or e-mail address contained unicode data.

Fixes test_page_scroll_on_thread_change_view failing on chrome

do orphan deletion in a bulk operation (SUST-21)

There are 3 main changes in this commit:
* CohortFactory now sets up memberships properly, so consuming tests do not
need to explicitly touch CourseUserGroup.users to add() users.
* test_get_cohort_sql_queries has been updated to 3 and 9 queries when using
and not using the cache, respectively. This is needed due to each operation
needing an extra queery to get the CourseUserGroup from the CohortMembership.
* Adding remove_user_from_cohort(), the counterpart to add_user_to_cohort().
This is also to keep tests from touching the users field directly, and keep
CohortMembership data in sync.

An issue arose recently due to ATOMIC_REQUESTS being turned on by default. It
turns out that CohortMemberships had been somewhat relying on the old default
transaction handling in order to keep CohortMemberships and the underlying
CourseUserGroup.users values in-sync.

To fix this, I've made all updates to Cohortmemberships go through an
outer_atomic(read_committed=True) block. This, is conjunction with the already
present select_for_update(), will no longer allow 2 simultaneous requests to
modify objects in memory without sharing them. Only one process will be
touching a given CohortMembership at any given time, and all changes will be
immediately comitted to the database, where the other process will see them.

I've also included some changes to get_cohort(), add_user_to_cohort(), and
remove_user_from_cohort() in order to properly make use of the new
CohortMembership system.

LMS: changing blue to pink, ensuring contrast, for Studio/Staff

MA-1742; return read status for GET thread details

Fixed test studio split test failing on chrome

Replacing user dropdown field with user search textbox. On stage due …

Fixed test cc and test arr license that were failing on Chrome

Allow using a custom login/register form with third_party_auth

Release-2015-12-01 conflict resolved

# Conflicts:
#	requirements/edx/github.txt

Modify existing Programs migration to account for help_text change

SOL-1417 Certs: Allow CSV upload for Cert Exceptions

Add pagination support to course catalog API

SOL-1389: Cert Exception: Add error states and messages

Support multiprocess bok-choy testing for discussion

SOL-1439: removed certificates delivered dependency on certificate eligibility

SOL-1466: Make sure web view renders certs only if downloadable.

* Catalog results are now paginated
* Implements the new namespaced pagination described at
  https://openedx.atlassian.net/wiki/pages/viewpage.action?pageId=47481813
* API level code returns pythonic business objects
* View layer performs serialize at the view layer
* Convert views to use DRF generic views
* Removes an unintentional authentication decorator that caused
  the detail endpoint to return a 401 for anonymous users

MA-1724

MA-1211; Discussion API - make boolean params case insensitive

Do not install xblock-utils in editable mode