There was a lack of "disk" space, when using memory.

This also makes the toolbox persistent over reboots.

It has not been updated since kubernetes 1.9 or so

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.

We can continue to add other tests to this file.