Ignored STATIC_ROOT and MEDIA_ROOT in makemessages

Also alleviate issues with weird file names typically found in
MEDIA_ROOT directories (#23010).
Thanks Tim Graham for the review.
Fixed #22998 -- Updated the fast_delete logic for GFKs
PEP8 cleanup
Added forgotten files from commit 28efafa24c83
Added Chrome/IE support for a selenium test.
Fixed #23023 -- Added warning against local-memory cache.

Thanks django at kerz.id.au.
Fixed #23041: Bad base dependencies for proxy models
Fixed reference to pk in RedirectView.get_redirect_url doc.
Added 1.6.6 release notes for #22998 (also forwardported those for #13794).
Alphabetized django.utils sections.
Edited setup.py in reuseable apps tutorial to use a context manager for open().