pass a MAC_ADDRESS variable

demonstrate passing from complete_create_vm_via_packer to create_vm_via_packer to config.json
BUGFIX: correct variable capitaliation
make headless
try using nat with specified port for ssh to guest
BUGFIX: remove escaped " in modifyvm natpf1 line
move "modifyvm ... --natpf1" to complete_create_vm_via_packer.sh else packer cant connect post setup
reinject mac setting: seems necessary
BUGFIX: remove escaped quotes in vboxmanage modifyvm natpf1
quote bash variables properly
natpf1 guestssh set in config.json; no longer necessary to set after VM creation
working crosscat install; needs to be fixed for none dlovell user
presume CachedPythonPackages is in same dir as config.json
correct ssh-keygen for NATd VM @ port 2222
script demonstrating process to go from untaring to connecting to VM
add some comments about how to power off and remove VM
use vmname instead of the imported vbox file path
use option keepnatmacs on import to obviate need to set mac