add note about killing PID 0 on POSIX
add note about killing PID 0 on POSIX

landryb/psutil,qbit/psutil,jorik041/psutil,jamesblunt/psutil,jamesblunt/psutil,cloudbase/psutil,cloudbase/psutil,Q-Leap-Networks/psutil,cloudbase/psutil,qbit/psutil,mrjefftang/psutil,landryb/psutil,landryb/psutil,msarahan/psutil,mindw/psutil,tomprince/psutil,jorik041/psutil,mrjefftang/psutil,packages/psutil,mindw/psutil,landryb/psutil,0-wiz-0/psutil,Q-Leap-Networks/psutil,tomprince/psutil,jorik041/psutil,tomprince/psutil,msarahan/psutil,giampaolo/psutil,0-wiz-0/psutil,qbit/psutil,mindw/psutil,landryb/psutil,tomprince/psutil,packages/psutil,jamesblunt/psutil,mrjefftang/psutil,packages/psutil,msarahan/psutil,mindw/psutil,mindw/psutil,tomprince/psutil,giampaolo/psutil