Added simple blockchain tests
Added simple blockchain tests

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