Added special case for pid 0 when determining username on Windows.
Added special case for pid 0 when determining username on Windows.

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