refactored syncing strategy
refactored syncing strategy

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