add helper to XOR binary string of arbitrary length
add helper to XOR binary string of arbitrary length

markope/AutobahnPython,oberstet/autobahn-python,crossbario/autobahn-python,RyanHope/AutobahnPython,Jenselme/AutobahnPython,crossbario/autobahn-python,oberstet/autobahn-python,crossbario/autobahn-python,tavendo/AutobahnPython,meejah/AutobahnPython,oberstet/autobahn-python