#309 Sessions remain open after deleting or updating a listener

[Stefan Bender]

According to the standard, all open sessions should be deleted and all timers stopped, when a listener is deleted or updated with new topo counts.
However, if this is done after a request is received, the listener's callback will still be called with an application reply timeout error (TRDP_APP_REPLYTO_ERR) once that timer has run out.