* Initial hack of worker-thread rearchitecture. Right now it is successfully

* Initial hack of worker-thread rearchitecture.  Right now it is successfully
  dispatching worker threads to active client sockets (and to the master
  socket too, of course).  Removing sessions is currently broken.  There is
  also a problem with worker threads waking up too quickly when a client
  command is entered (race condition?).   More cleanup to follow.