contracts now compile with python 3 bytestrings
contracts now compile with python 3 bytestrings

ethereum/pyethereum,ddworken/pyethereum,holiman/pyethereum,shahankhatch/pyethereum,ckeenan/pyethereum,karlfloersch/pyethereum,vaporry/pyethereum,pipermerriam/pyethereum,shahankhatch/pyethereum,ethereum/pyethereum,inzem77/pyethereum,harlantwood/pyethereum,karlfloersch/pyethereum,pipermerriam/pyethereum