move snapshot details out of the main scope (and into per-vm scope)?

What if we moved all the multiline snapshot details from the main `valine` output and into the per-VM output (e.g., `valine SOMEVM`) ...?

We could then keep the main `valine` output to 1 line for each VM ... and we could add mem/cpu limit details -- maybe even including `virt-top` percentages as mentioned in another issue. I'd love to get some feedback from people on this.
