0.5.0 introduces a new way to configure the containers and execs. This
is now done all upfront at constructor time in a callback style. I'm
very happy with the config improvements, but because IO can only be
setup at constructor time this makes it so that we need to supply IO at
creation time of the VM or exec, which isn't the end of the world. All
that really changes is `boostrap()` and `createProcess()` now take in IO
instead of slightly later in `process.start()`