Implement -k switch to use self signed certificates, cli parameters cleanup

[juzam]

This PR implements -k command line switch (-k inspired by cURL) in order to connect to a mqtt broker with TLS and self signed certificates (or certificate signed by a non trusted CA by default)

As per mqtt.Client(streamBuilder, options) it is done by passing rejectUnauthorized: false as an added mqtt connectio option. Defaults to false.

Also cleaned up a bit -l logging option adding proper .choices in config.js
-h and Readme changed accordingly

[svrooij]

What does this row do?

[juzam]

that disables yargs default usage output (which is 80 columns) basically demaning -h usage output wrapping to the terminal. (ref doc .wrap )[https://github.com/yargs/yargs/blob/HEAD/docs/api.md#wrapcolumns]. It's purely cosmetic, unfortunately I couldn't find a way to wrap properly by using something like .wrap(yargs.terminalWidth()) as suggested in the docs.

[svrooij]

@juzam I fixed the travis error, so you can ignore that but could you have a look a my comments?

[juzam]

@svrooij thanks for fixing the travis check (I didn't know it was broken prior to submitting the PR, sorry). See my comment to the .wrap line. That's not mandatory, but I thought that the usage output was clearer without the hardcoded wrapping at 80 columns by default.

[svrooij]

I like short code, could you change this to the following?

  const mqttOptions = {
    will: {
      topic: config.name + '/connected',
      message: 0,
      qos: 0,
      retain: true
    },
    rejectUnauthorized = !config.insecure
  }

[svrooij]

Did you see this comment? https://github.com/svrooij/node-xiaomi2mqtt/pull/7/files#diff-20ff7b6cac52b690c1376c3d56b4a959R30

[juzam]

@svrooij argh, I missed the comment. should be fixed now.

[svrooij]

It is now released in npm. I still think getting an official certificate isn’t very hard (like for free with lets encrypt), but that is up to you.