RFE Add to the README the mount commands to run chroot into the images

[emdee-is]

I love the idea - it's very simple and efficient.

virsh is using linux's overlay filesystem to layer the writeable qcow over
the base qcow.

With the instance shutdown, both images can be mounted using qemu-nbd.

If mount disks are available using nbd, can you put into the README
the two lines you would need to replicate the overlay mount using mount,
with the instance not running.

Then you could chroot into the combination. as well as running it as a VM.