Fix up rvalue references. Avoid a copy of an EVM code in ExtVM.
Fix up rvalue references. Avoid a copy of an EVM code in ExtVM.

arkpar/solidity,vaporry/solidity,ruchevits/solidity,douglas-larocca/solidity,chriseth/solidity,ruchevits/solidity,gluk256/solidity,shahankhatch/solidity,debris/solidity,ruchevits/solidity,LianaHus/solidity,chriseth/solidity-doc-test,ruchevits/solidity,ethers/solidity