added externalTypes function to functionType removed flag for externalSigniture
added externalTypes function to functionType
removed flag for externalSigniture

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