add: handy wrap of recursive_int_to_big_endian and rlp.encode
add: handy wrap of recursive_int_to_big_endian and rlp.encode

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