Starting the CHANGELOG process.

Squash 3 more naive datetime warnings. I think the only ones left are in

dummy object creation without conditionals

added comment to make clear that leaving the variable analytics outside of the feature flag block is intentional

migrations.

Conflicts:
	common/lib/xmodule/xmodule/capa_module.py
	common/lib/xmodule/xmodule/fields.py
	common/lib/xmodule/xmodule/peer_grading_module.py
	common/lib/xmodule/xmodule/tests/test_fields.py
	requirements/edx/github.txt

Fix formatting problem in README.md 

message to explain why this merge is necessary,

Make video captions respect course author's setting.

Do a bundle install before trying to use rake, so that we have all the p...

Fix tests that vary urls.py

(cherry picked from commit 14100ba1)

(cherry picked from commit 832da3ad)

(cherry picked from commit 050846af)

(cherry picked from commit 664efb98)

(cherry picked from commit a17bf5e2)

(cherry picked from commit 273df4e1)

(cherry picked from commit c96511a2)

(cherry picked from commit 1511ec84)

(cherry picked from commit d2554909)

Problem Show Answer/Check Button Line Height Syncing

added pylint ignores, fixed missing import