added clean option to setup.py
added clean option to setup.py

caidongyun/pyzmq,swn1/pyzmq,yyt030/pyzmq,caidongyun/pyzmq,ArvinPan/pyzmq,Mustard-Systems-Ltd/pyzmq,dash-dash/pyzmq,yyt030/pyzmq,swn1/pyzmq,dash-dash/pyzmq,caidongyun/pyzmq,ArvinPan/pyzmq,dash-dash/pyzmq,Mustard-Systems-Ltd/pyzmq,swn1/pyzmq,Mustard-Systems-Ltd/pyzmq,ArvinPan/pyzmq,yyt030/pyzmq