[product: zaphod][project: zaphod-v0.3]: Remote command exection for testing

SYNOPSIS
[modified]m42/test/zaphodtestutil.py: Implemented execute_remote_command

DETAILS
A simple implementation of remote command execution for use by
test scripts. The code simply logs into a newly created
VM (assuming NAT networking mode) and executes the specified
command. The code has not been tested.