Incompatibility with node 12

[mrbuds]

$ moonshine distil api.lua
fs.js:151
    throw new ERR_INVALID_CALLBACK(cb);
    ^

TypeError [ERR_INVALID_CALLBACK]: Callback must be a function. Received undefined
    at makeCallback (fs.js:151:11)
    at Object.unlink (fs.js:1041:14)
    at C:\Users\buds\AppData\Roaming\npm\node_modules\moonshine\bin\commands\distil.js:170:6
    at ChildProcess.exithandler (child_process.js:294:7)
    at ChildProcess.emit (events.js:311:20)
    at maybeClose (internal/child_process.js:1021:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:286:5) {
  code: 'ERR_INVALID_CALLBACK'
}

This is fixed by replacing in bin\commands\distil.js line 170

fs.unlink(luacFilename);

with

fs.unlinkSync(luacFilename);