refactored miner to update on transactions
refactored miner to update on transactions

ethereum/pyethereum,jnnk/pyethereum,harlantwood/pyethereum,karlfloersch/pyethereum,vaporry/pyethereum,pipermerriam/pyethereum,shahankhatch/pyethereum,holiman/pyethereum,ethermarket/pyethereum,ethers/pyethereum,ddworken/pyethereum,inzem77/pyethereum,ethereum/pyethereum,pipermerriam/pyethereum,ckeenan/pyethereum,ebuchman/daoist_protocol,ebuchman/daoist_protocol,shahankhatch/pyethereum,karlfloersch/pyethereum