Note to self and KOHSUKE (This may need some hooks in the core - your thoughts
please) [This is _not_ the load test use case]

Want to be able to have hudson start & stop slaves that are Virtual Machines as
required.

1. If no builds need the slave for a configurable idle time, suspend/power off
the Virtual Machine that it is running in (conserving resources on the VMware Host)
2. When a build needs to run on a slave that is powered down, power up the
Virtual Machine and let the build start
3. If the idle time is zero, start the Virtual Machine when Hudson powers up,
and shut it back down again when Hudson is Preparing for Shutdown and all
running jobs on that Virtual Machine have completed.