Use Sidekiq instead of Resque.

Sidekiq will, with any luck, enable much more processing on the tunefl
server. Besides, it's pretty darn cool. :D

There is no /sidekiq mounted; if you'd like to monitor in development,
you can still use `resque-web` by setting `WORKER_REDIS_NS=resque`. ;)
Remove unused helpers,files,.gitkeeps.

Feel free to add things again if they're needed, but otherwise might
as well clean up. :)
Change README extension to md.
Delete config/database.yml.

This is very exciting! As of Rails 3.2, `DATABASE_URL` can be used
instead of reading config/database.yml. Hurrah! :D
Add missing requires.

Everything works, but...
Change ENV vars to lowercase, unless magical.

In order to reduce pollution, use lowercase ENV vars.

    http://pubs.opengroup.org/onlinepubs/007908799/xbd/envvar.html

Retain PORT,DATABASE_URL, however, as these are more magical than the
others. Perhaps these will be changed at some point.
Document need for ENV vars when rake,rspec, and generally update.
Change CompileScoreWorker to use Dir.tmpdir instead of tmp/.
Merge branch 'splendiferous-things' into develop