Backported changes to vexer.py
Backported changes to vexer.py

terry2012/angr,cureHsu/angr,chubbymaggie/angr,terry2012/angr,avain/angr,xurantju/angr,GuardianRG/angr,lowks/angr,chubbymaggie/angr,schieb/angr,f-prettyland/angr,schieb/angr,iamahuman/angr,avain/angr,tyb0807/angr,zhuyue1314/angr,iamahuman/angr,angr/angr,xurantju/angr,chubbymaggie/angr,angr/angr,schieb/angr,axt/angr,fjferrer/angr,GuardianRG/angr,zhuyue1314/angr,lowks/angr,haylesr/angr,mingderwang/angr,iamahuman/angr,angr/angr,cureHsu/angr,tyb0807/angr,haylesr/angr,tyb0807/angr,f-prettyland/angr,fjferrer/angr,axt/angr,mingderwang/angr,f-prettyland/angr,axt/angr