Add a __repr__ method in s_irsb.
Add a __repr__ method in s_irsb.

chubbymaggie/simuvex,axt/angr,angr/angr,chubbymaggie/simuvex,f-prettyland/angr,chubbymaggie/angr,f-prettyland/angr,f-prettyland/angr,iamahuman/angr,axt/angr,schieb/angr,angr/angr,axt/angr,schieb/angr,chubbymaggie/angr,chubbymaggie/angr,iamahuman/angr,tyb0807/angr,angr/angr,iamahuman/angr,schieb/angr,zhuyue1314/simuvex,tyb0807/angr,chubbymaggie/simuvex,angr/simuvex,tyb0807/angr