Previously we were mixed between the two forms. This commit picks %v,
which is consistent with the Kubernetes code base. They both effectively
do the same thing in this case, though %v works with any object, and %s
only with string objects.
* Separate start args from args passed to every command. This is so
that we can call `minikube logs` and `minikube status` with the proper
flags (for the bootstrapper)
* Add a NewMinikubeRunner function to make getting a minikube runner
easier.
Thomas Strömberg
Anders F Björklund
Aaron Prindle
Matt Rickard
dlorenc