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.
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
Remove extra prerequisites style and add classes
Add compare-branch option to paver run_quality
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
Merge pull request #6123 from mitocw/bdero/move-course-role-check-to-student

Moved has_course_access from CMS to student.auth (common)