Failed to close out-of-process marshaling in case of lingering host

[jasper]

Once the marshaling connection is closed by the PME process, the PMC process failed to close the connection because this action did not cause the transport channels to be marked as closed, causing the transport destructor to wait indefinitely for the transport threads to finish.

So far this situation did not occur due to the connection being marked closed upon the ProcessMonitor? component detecting that the host process no longer exists (upon which the channels are marked as closed), but in case the host process would continue, also this would not happen.

Detected because #200 failed to start up the ProcessMonitor? in case of an out of process PMC host.

[jasper]

Fixed by commit [25d1b98ffc3473747fb3d83988921a23b45e23f4]