Nodejitsu support, per-environment configuration, ability to remove Facebook/Twitter from config

Separated config files on a per-environment basis

Consolidated the config require statements down to just one.

Made sure that the Redis client object gets passed to all the correct places (otherwise you get weird errors where some node_redis operations try to use the default client options instead of those from the config).

Made it so that the application doesn't bomb out when either Twitter or Facebook is missing from the config.

Added a Nodejitsu config sample and then some Nodejitsu-required stuff to package.json.

Updated the README to reflect the new configuration file structure.