dmsg - Stabilization work

dmsg - Stabilization work

* Refactor the circuit failure handling code.  When a connection is lost
  circuits running through that connection and all sub-circuits/states
  (recursively) are aborted.  This will propagate through the graph and
  there are plenty of edge cases where a failure may be propagating in
  one direction and a request in the other direction.

  The library is responsible for providing missing transaction closures
  when circuits and states fail.

* Add code to handle circuit failure races against newly created messages.
  The STATE_DYING flag is now inherited by the newly created message from
  its parent.

* The state structure on receive is now updated before the callback is
  made so it can be atomic with the lock, instead of after.

* Lots of debugging added and some cleanup.