Added support for environment variable default value
Fixed pep8 warning
Fix Dockerfile for new config locations

Commit 900d26221805889e617a11aa0f67ab04e5252491 should have included this.
Require Boto v2.19.0 to work with IAM role

There is an issue with Boto v2.3.0 using IAM role to access S3.
As mentioned here (https://github.com/dotcloud/docker-registry/pull/72),
when 4 or more gunicorn worker process are trying
to fetch metadata for accessing S3, the requests are
throttled by Amazon and thus fail to launch the server.

Boto v2.10.0 and later introduces metadata_service_timeout &
metadata_service_num_attempts to resolve this issue.

This PR also comes with a Boto config file at /etc/boto.cfg to
increase default metadata timeout & attempts.
Move boto.cfg into config/
Renamed config directive "cache" to "cache_lru"
Documented cache_lru in the config sample
Added LRU cache explanations in the README
- Added bandwidth_parser script that reads from docker-registry's log file
	- Keep the data in redis for 24hs
- Added config environment for prod/redis
- Refactored the bandwidth_parser
- Removed bandwidth_cache file
- Added the posinstall script to add a crontab job
- Changed the name of the redis instance
some cleaning
Added some private config files to ignore list
added openstack swift backend
Merge branch '106-swift-storage' of github.com:bacongobbler/docker-registry into 106-swift-storage