Ejp to hw zip workflow

The code used in production right now.

Notable edits:
* example-settings.py directories no longer have trailing slashes
* changes to other directories and settings to wire into elife-bot
* allows various version of gitpython (using an exception)

Main features are the repackaging of article zip files, decapitating PDFs, batch zip packaging, FTP transfer and other parts to enact the workflow.