Specify app name, and more in settings #16

Currently it's not possible to specify the name of the app you are creating logs for via the settings.

I would like to do something like this

stackify.start({apiKey: '****', env: 'development', appName: 'MyAwesomeApp'...})

And be able to create logs that would appear in the reporting as MyAwesomeApp so that it's not depending just on the packaje.json name but also something that I can configure differently