mitigate child processes with 100% CPU and/or zombies

This should work around the 100% CPU and/or zombie issues (for details see commit log).
It does *not* fix the root cause of the endless loop in the child processes, but it kill's them, so they don't live very long.

This is by no means good code, but a works-for-me with some ugly hacks.
Should probably be refined or tested by more people than just me before a merge :-)
(is there an experimental or -dev branch?)