randomize_module.py was missing 'import lxml' to support definition_to_xml(). Also, fix serialization of show_timezone to expect a bool

The most common error is Amazon SES having blacklisted an email address.
However, we handle any error being raised during user.email_user.

Fixes JIRA LMS-131

Django always returns string data from the database as unicode objects
(ref: https://docs.djangoproject.com/en/1.4/ref/unicode/#models).
Therefor, our factories should do the same

This reverts commit 90a9c386.

Because there are some cases where it's OK to fail, and it's not the user's fault

add a migrations to the new django_comment_common to keep things a bit more consistent with our normal useage.

Check functions need access to course-local code also, so we need to save the python path from the problem setup, and use it for the check function.

studio - adds back in older lh() Sass function/mixin and moves it to the inheritied/to-be-sunsetted mixins sheet

This resolves an issue on Mac OS X in which the login dropdown
arrow couldn't be clicked because it was off-screen.
It should make the test suite more stable.

#324

the actual urls

getting closed fast enough.

From code review: the hash was shallow, so nested objects could have hashed differently when they didn't need to.