Fixed signed representation of 2^255
Fixed signed representation of 2^255

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