added more explanation of elevated shell
added more explanation of elevated shell

ClogenyTechnologies/knife-windows,chef/knife-windows,MsysTechnologiesllc/knife-windows,RobbertJanSW/knife-windows,MsysTechnologiesllc/knife-windows,RobbertJanSW/knife-windows,ClogenyTechnologies/knife-windows,chef/knife-windows