Unstable thread termination
It is possible that a thread remains in SpScPipe.add() and hence does not terminate. Furthermore, terminate() is not synchronized. This is needed for the exception handling to work. (slightly related to #130 (closed))
It is possible that a thread remains in SpScPipe.add() and hence does not terminate. Furthermore, terminate() is not synchronized. This is needed for the exception handling to work. (slightly related to #130 (closed))