Adding some code comments and general cleanup
creating a new general Helpers library
FSE-112: by default, when you run `knife container docker build` against a docker context initialized against a Chef Server, the node and client objects that are created are deleted after the image has been built.
creating a new general Helpers library
FSE-112: by default, when you run `knife container docker build` against a docker context initialized against a Chef Server, the node and client objects that are created are deleted after the image has been built.
reworked docker_build tests to use expect syntax; now use mixlib-cli properly per @ssd's feedback
Merge branch 'tduffield/FSE-112' of github.com:opscode/knife-container into tduffield/FSE-112

Conflicts:
	lib/chef/knife/container_docker_build.rb
	spec/unit/container_docker_build_spec.rb
somehow my rebase got f-ed up and I needed to redo some changes.

This branch has been a nightmare.
Merge pull request #6 from opscode/tduffield/FSE-112

FSE-112: cleanup chef artifacts after docker build