Pause functions

Both listeners and dispatchers can be paused. they can be paused fully
(retains buffer without add() or flush() in the case of dispatchers) or
the input or output can be paused individually. 'pause' replaces
'active' more robust than 'active' as true is paused, therefore omission
is active by default, also more variants of 'true' accepted plus
variants of 'in' or 'out' for partial pause.