Remove build cruft.
Remove build cruft.

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