Compilation fails with solc 0.5.8

Error:
```
/lib/dappsys/stop.sol:33:34: TypeError: This modifier uses "msg.value" or "callvalue()" and thus the function has to be payable or internal.
    function start() public auth note {
                                 ^--^
/lib/dappsys/note.sol:36:20: "msg.value" or "callvalue()" appear here inside the modifier.
            wad := callvalue
                   ^-------^
```