Add support for version arg

[jaa127]

This PR add support for reporting version info from apps (cli, gui). To support that, it refactors and cleans up cli Main-method vs. App logic. Now "extends App" is removed and it is plain object with main.

This also paves road for #115.

[coveralls]

Coverage decreased (-0.3%) to 68.879% when pulling a23390b on jaa127:version-arg into ceb7716 on hrj:master.

[hrj]

I understand what you are doing here, but I think having two different versions (base version + app version) is complicating it too much and might lead to confusion.

And when making releases, in the foreseeable future, I am not planning to release app and base separately.

So, let's keep it simple for now. Only one version should be shown to users.

[coveralls]

Coverage decreased (-0.2%) to 68.966% when pulling 9029490 on jaa127:version-arg into ceb7716 on hrj:master.

[jaa127]

Hi, do you have any change to comment this or merge if this is ok? I have other stuff in pipeline, and this is kind of blocking that stuff. In anycase, happy holidays!

[hrj]

I have merged this trusting that you have done the right thing. Happy holidays to you too 😄

I was not sure why the "throw" related changes were done. There was some problem in the past related to running the app and throwing of exceptions. But I don't recall now and I am travelling. So I am turning a blind eye on it 😉

[jaa127]

Cool, thanks. It should be ok. Code was doing System.exit on that spot. This was not ideal, and there are already other exceptions passing through on that spot, so this new throw won't be a problem.

Moreover, App code is gone and it is plain object + main(args: Array): Unit. And in any case this is easier to handle than App logic (imho).