Garbage Collection - Free image space
Pull from default config for gc settings
Images will be removed when expiration is reached
Updated package dependencies for diskspace
Fixed tests, added comments, and remove all images if threshold is met
Fixed poor use of passthrough stream.  Pipe everything to stdout now.
use worker config for docker volume and improve logging
Pull image with 'latest' tag if no tag specified
Remove duplicate code for parsing image name
Fixed up some formatting and added some useful comments
Merge pull request #44 from gregarndt/garbage_collect_images

Garbage Collection - Free image space