Fix terminate() issue

[simonkrauter]

See #1558

[jovial]

Is it worth having a "stronger" function, kill, like in the python multiprocess api? Then have terminate only send a sigterm? That way if you have a load of processes that take a while to shutdown, you just spam them all with a terminate and check their exit codes at later time (instead of waiting on each individually).

Also, you might not always want to send a sigterm to the whole group. What if the process takes care of sending a signal to its own children?

The python implementation of kill on windows is just another alias for TerminateProcess. It's worth noting that this only terminates the one process, so for cross-platform code, we might want to replicate this in the posix version (at least by default).

[simonkrauter]

Please move your comment to #1558 , so we have all discussion at one place.