Move submodules to app/lib and appver to settings.
Merge branch 'master' into develop

Conflicts:
	app/.env
	app/lib/ebooklib
	app/lib/pyphen
	app/lib/readability
Merge environment vars with .env settings

The .env file is usually used by Heroku's Foreman to set environment
variables for local runs. We extend this idea and use this same file to
set up the environment in production as well, also on App Engine. This
allows removing common environment variables from app.yaml and
better conformance to DRY.
Merge branch 'develop' to 'master'
Fix .env line endings and upload to GAE
Add installation instructions
Fix bug in html handling

Because of this typo, html was mistakenly handled
as pdf when Readability extraction failed.
Improve installation instructions

- Add separate `requrements_gae.txt` so that unnecessary
packages won't get installed on GAE. E.g., the production
environment already has lxml, jinja and markup packages
pre-installed, so no need to upload them to the server;
- Verbose output in runtime for setting Readability token
and Google tracking ID; therefore, don't submit fake values
in app/.env;
- Improve installation instructions in README.md;
- Increment minor version number.
Merge branch 'master' into gh-pages

Add installation instructions in README.md