Fix help modal css selector
Remove antiquated cleanup script

This script was originally written to clean up XML scripts. In the more
than two years since it was originally written, the only updates it has
received have been to remove PEP8/PyLint/quality violations.

It's hard to imagine that this is still useful to anyone, though I'm
open to discussion.
config refactor wip
merging from master
pep8 and comments
Moved has_course_access from CMS to student.auth (common)
Change has_course_access definition and doc string

- has_course_access renamed to has_course_author_access for clarity
- Changed doc string to clearly state that it determines whether or not
  a user has write access to a course
Split mongo support for libraries and Library XBlock
renmaing prod.py and setting more defaults
Remove extra prerequisites style and add classes
renaming to use underscores
Add compare-branch option to paver run_quality
Don't allow voting while the thread is closed

When someone closes thread there is still option
to add vote which cause error when click on add
vote button. User shouldn't be able to add vote
while the thread is closed.

TNL-152
Merge pull request #6064 from Stanford-Online/kluo/quality-compare-branch-option

Add compare-branch option to paver run_quality
Merge pull request #5842 from Stanford-Online/giulio/prerequisites-style-fixes

Remove extra prerequisites style and class
Merge pull request #6065 from stvstnfrd/debt/xml-cleanup

Remove antiquated cleanup script
Pin django-cas to hash
Move to github.txt and make editable
Add base support for cohorted group configurations

TNL-649
Add support for user partitioning based on cohort.

JIRA: TNL-710

IMPORTANT: this commit converts the course_groups
package to using migrations.  When deploying to an
existing openedx instance, migration 0001 may fail
with an error indicating that the CourseUserGroup
table already exists.  If this happens, running
the 0001 migration first, with the --fake option,
is recommended.  After performing this step,
remaining migrations should work as expected.
Add group_access field to all xblocks

TNL-670