Remove CRLF line endings everywhere they appear

* Nothing else touched in this commit
* Produced by running the following:
    for file in `find . -iname '*.py' -o -iname '*.txt' -o -iname '*.html' -exec file {} \; | grep CRLF | cut -d':' -f1`; do
        dos2unix $file; git add $file;
    done && C2G_HEADLESS_TESTS=1 REUSE_DB=1 ./manage.py test -v 2 && git commit
Merge pull request #2161 from Stanford-Online/jrbl-2125-jrbl-hates-crlf

Remove CRLF line endings everywhere they appear