Change Details

See https://github.com/EyeOfPython/bitcoincash.org/blob/master/spec/op_bswap.md

See https://github.com/EyeOfPython/bitcoincash.org/blob/master/spec/op_reversebytes.md

See https://github.com/EyeOfPython/bitcoincash.org/blob/master/spec/op_bswapreversebytes.md