add ability to test using Docker

Instead of having to constantly be pushing code to github and rebuilding in ominbus chef, this code allows you to build and test the gems locally using Docker.
change how we handle exits

use true/false instead of ints for exit codes; use HUP all the time with RUNIT otherwise the runsv stuff will be left alive
shift around some helper code

shift around some code to make it more usable/readable
bump version to 0.3.0.dev