Added support for getting strings and data refs.
Added support for getting strings and data refs.

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