[Vortex] [patch] partial patch for dependencies on msg ordering

[Sam Roberts]

The dependency on msg ordering is pretty wide-spread.

I removed assumptions about order or received messages. However, that
causes reply to be broken:

(proc 6436): (warning) vortex-channel: Received a rpy request for
message 102 while already waiting to reply to 0, storing and unlocking
caller for later deliver

That reply will never get delivered,.

The unreplied msgs needs to be an ordered list, not a set, so that
replies can be made in same order as reception.

I'll keep going with the patch if you are interested in it. If you'd
like to fix this yourself, or just don't want to fix it all, I'll
leave it.

Cheers,
Sam