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