Client side options for changing retry behaviour

Added two new command line options to client:

  * -noRetryAfterConnected
    * Exit client after a successful connection is closed. This makes it possible to use the "Delete Slave" functionality in Jenkins without having the slave come back again 10 seconds after it was deleted.
  * -retry
    * Option for limiting the number of retries before the client exits. The default behaviour is still to retry forever.