Upgrade `requests` module to 2.3.0
Upgrade `requests-oauthlib` to 0.4.1
Upgrade `oauthlib` to 0.6.3
Add argument.
Remove unused code when download from youtube.
Merge pull request #4026 from edx/db/requests-2

Upgrade `requests` module
Update the discussion area broken span tags
FOR-578
Merge pull request #4105 from edx/alex/remove_unused_code_when_downloading_from_youtube

Remove unused code when download from youtube.
dummy theme templates for testing
tests for PR 3769

Two out of three fail without PR 3769 but all pass with PR 3769.
Merge pull request #3770 from mlkwaqas/waqas/for578-post-selection-broken-span

Update the discussion area broken span tags
Merge pull request #4201 from edx/jtauber/test-PR3769

Test PR 3769 (Improves the way LMS serves /favicon.ico)