Klever

There are rare cases when python multiprocessing or subprocess (don't know exactly who is in charge of this) process communication methods do not successfully register the child process termination. This leads that control from task has never returned and it is considered as processing even when the corresponding process is dead. This is hard to reproduce and even harder to debug, but we can add additional checks of running state to be aware of such cases or implement an another way of running child processes in the native scheduler.