Upgrade `requests` module to 2.3.0
Upgrade `requests-oauthlib` to 0.4.1
Upgrade `oauthlib` to 0.6.3
Add argument.
Add scope/field selector settings for LinkedIn provider.

This change adds three new configuration variables to third_party_auth's LinkedIn provider:

* SOCIAL_AUTH_LINKEDIN_OAUTH2_SCOPE,
* SOCIAL_AUTH_LINKEDIN_OAUTH2_FIELD_SELECTORS,
* SOCIAL_AUTH_LINKEDIN_OAUTH2_EXTRA_DATA

Being able to configure these additional settings is useful if you want
the LinkedIn provider to pre-populate the email field when a new user
registers via the linkedin provider.

The Google provider prepoulates the email field by default, but if you
want LinkedIn to do the same, these two settings should be set to:

SOCIAL_AUTH_LINKEDIN_OAUTH2_SCOPE = ['r_basicprofile', 'r_emailaddress']
SOCIAL_AUTH_LINKEDIN_OAUTH2_FIELD_SELECTORS = ['email-address']

For more info see:
http://psa.matiasaguirre.net/docs/backends/linkedin.html
log stop_video event
Remember the user last thread sort preference
FOR-545
Merge pull request #3738 from mlkwaqas/waqas/for545-user-last-thread-not-remembered

Waqas/for545 user last thread not remembered
Remove Flash Test Scenarios
The LMS should serve favicon.ico also when a theme is enabled.
Set position for collapsible.js full-bottom link.

Currently it is covering the whole parent div.

LMS-2852
Fixes: DOC-599
Merge pull request #4142 from edx/ahodges/documentation/DOC599

Fixes: DOC-599
Add info about Mandarin Chinese option to LMS
Merge pull request #4149 from edx/sylvia/docs/release_notes_6_16

Add info about Mandarin Chinese option to LMS
Tracks last edited date and user, and adds has_changes for blocks.
link to code ownership page from CONTRIBUTING.rst file
Merge pull request #4152 from edx/db/code-ownership

link to code ownership page from CONTRIBUTING.rst file
Wait for scripts defined in common xmodule code to execute.

STUD-1792
Merge pull request #4060 from edx/benmcmorran/edit-tracking

Tracks last edited date and user, and adds has_changes for blocks