TNL-2695

Skipped 'print' statement violations, as print() is Py3k syntax.

TNL-2619

Extends the common capa response types (string, numeric, multiple
choice, checkbox, dropdown) with feedback and hint
capabilities. "Feedback" refers to feedback shown to the student when
they check the problem, looking at their specific answer. "Hints"
refers to a Hint button in LMS which the student can click at any time
to see hints for that problem. The implementation extends the markdown
syntax to include feedback and hints. There are new Feedback-and-Hint
specific templates in Studio when the author clicks to add a new
problem.

TNL2159

Converted lettuce Course Team page tests to bok choy

This is needed for courses that license video content where the license
allows only for viewing on the web, not on mobile apps.

JIRA: MA-307

Most of the updates are related to the My Courses -> Studio Home change.

Clear the 'invalid login' error message when the user edits her username
or password.  This fix makes makes it clear that future attempts to
login are not being ignored if they continue to generate the same error.

Add an acceptance test case to verify this behavior.

Fixes https://openedx.atlassian.net/browse/TNL-140

TNL-997

for visual indent

for hanging indent

visual indentation