This adds a cap on dnspython, feedparser, python-dateutil. The

first two have newer versions requiring Python 3. The latter does not,

but we're preparing ourselves.
There's also a bump on pillowfight, which has been updated to properly

cap Pillow versions.
publicsuffix is no longer getting new releases (we will need to update

versions later. pytz still advertises explicit support for all

versions of Python 2.4 and higher, so it seems unlikely we'll need to

worry at the moment.

Installed in a new virtualenv and verified that the installation completed

without errors.