Making the command array into a command matrix

(so we can more easily inject the setup and teardown tasks as well as
handle container searching before tagging
Pulling the dockerclient out of the parser

since it doesn't really belong there.  The ID of the image we're tagging
has to be determined while we're building, so it'll get moved into bob
eventually
Adding a docker client to bob and implementing LatestImageTaggedWithUUID
Making sure we pass docker tag args to `docker tag` commands
Adding name to the InstructionSet ContainerSection
Refactoring the data structure that passes commands to the builder

Before we weren't passing the metadata necessary to actually do the
building
Adding a little more info to our example builderfile

to make it easier to test bob
Adding fixtures for bob tests
Implementing directory setup and teardown for temporary build dirs
Adding comments to make lint happy
Making sure dockerfiles are named "Dockerfile" when copied into workdir
[TRIVIAL] updating placeholder comments for Build()

[ci skip]
The bob test file can be in the bob_test package now

while writing the tests I was testing some private methods, but I have
since refactored
[TRIVIAL] Renaming the helpers file
Merge pull request #3 from modcloth/filling-out-more-stuff

Filling out more stuff