vag.mk: add snap-status at end of example
remove deprecated code from boot script
many fixes to prepare for going prime-time

- add 'disable' to actually de-activate snapshots
  and use the original LVs (e.g. for installing 
  system updates)
- don't use sudo when running in boot initrd
- add Makefile for running vagrant tests
- add mini install.sh for simplifying tests
- add test scripts and *very* basic Vagrant class for
  accessing the Vagrant instance during tests