Memo transaction

Post memo These bch-js examples show how to read and write OP_RETURN data on-chain: https://github.com/Permissionless-Software-Foundation/bch-js-examples/tree/master/low-level/op-return
Reply to memo 3704c1a2b61c665fe5751e4e3fe38d83007d6efd06e8c93df8b076683a23c221