[ros-kernel] Cancel-Safe Queues

[Vizzini]

All,

I have committed a cancel-safe queue library that I have been working on
for a few days.  It is a complete re-implementation of the CSQ library
that made its appearance in the XP DDK.

Please take a look at reactos/drivers/lib/csq if you're curious.  This
stuff is very difficult to get right, and I'm sure there are mistakes. 
It does, however, test cleanly against the DDK-supplied cancel stress
application.

I'm going to use this to clean up various IRP-queuing issues I've run
across in the past few months.  I'd suggest that new drivers be written
to use this logic as well, so as to concentrate all cancel-related bugs
in one place.

Feedback appreciated.

 -Vizzini