[NTOS]: Have I/O Manager Volume Device Objects register with the Power Manager so...

[NTOS]: Have I/O Manager Volume Device Objects register with the Power Manager so that they can receive dope.
[NTOS]: Reimplement NtShutdownSystem.
[NTOS]: Implement NtSetSystemPowerState for the shutdown/reboot cases.
[NTOS]: Use the dope from the volume device objects to flush all writeable (non-floppy) devices. Pending hard-disk changes are now flushed to disks before shutdown.
[NTOS]: Flush \\REGISTRY during shutdown. This flushes all pending changes.
[NTOS]: Call into Cc to flush lazy writer during shutdown.
[NTOS]: Stop killing processes on shutdown. The kernel should not be doing this.
[NTOS]: Don't only shutdown disk file systems, but also cdrom and tape.
[NTOS]: Don't only notify drivers of first-chance shutdown -- also parse the last-change shutdown list.
[NTOS]: Reference drivers registering for shutdown notifications so that they remain loaded for them to get the notification at shutdown.
[NTOS]: Notify drivers that have registered/opened the Power State callback.
[NTOS]: A lot of the Po* power state code is highly simplified, but provides a good roadmap to anyone interested in this functionality long-term.

svn path=/trunk/; revision=46004