Add pdf.js as a submodule
Include pdf.js from extension build script

With this change, I have no problem testing a local chrome extension
build.

Close #891
Update extension installation instructions

Closes #1080
Add production.ini and strip down development.ini

The Procfile now uses production.ini which should use a set of sane
defaults and includes more comments to explain what's going on.
Add support mail settings from environment
Prefer environment variable for ES connection
document docker links
support DATABASE_URL env variable