Converted weekly email stats to a Celery task. Fixes #479
closes #517
Updated Vagrant install doc. Need to install dependencies first.
Needed to copy settings from example to my own instance for
Vagrant based install. Freshened up install instructions
Switched to use the built in Django timezone aware logic to display
times and dates in templates. fixes #514
Merge branch 'develop' of github.com:harvard-lil/perma into develop
Took another pass at displaying times in the user's local time using
the JS approach (get the user's TZ info from their browser and
adjust our UTC date using JS in the users browser at loadtime.)

Using the moment.js lib which seems to be well regarded.

fixes #514
Fix source playback in use_warc=True mode.
Merge pull request #518 from jcushman/dev.warc2

Fix source playback in use_warc=True mode.
Add custom server_error views so that we can send REQUEST_CONTEXT [and thus get STATIC_ROOT]
Make the <title> of the 500 error say '500' instead of '404'
Fix typo in urlconf for upload_link URL
Some celery config for wsgi.py
Add phantomjs file variants in lib/phantomjs to .gitignore
Make sure the 404 and 500 views return the right status codes
Merge pull request #521 from leonidg/leonidg-misc

Leonidg misc merge. Some cleanup and a
Some JS was breaking when being jammed together by django-pipeline.
Fixed, I hope. Fixes #524

Also ran into a string concat issue in models. Fixed.