Improved KShell Launcher README

[seanabraham]

Looks like the kshell_launcher is pretty alpha right now, but it might be worth noting in the README that in order to get it to work, you'd have to clone the sparklin repo and mvn install to get it to work. It looks like neither sparklin:jline3-shaded nor sparklin:kshell are on Maven Central or JCenter.

[seanabraham]

Also, it looks like the current implementation fails to resolve @file:Include lines currently because the files don't exist relative to the tmpfile that's created with the kshell headers. I can put up a PR to fix that if you want, but there would be a bit more work required in recursively parsing all the included files for @file:DependsOn annotation. Alternatively, we could assume everything was depended on in the top level file and just ignore the @file:Include annotations.

[holgerbrandl]

It is a indeed more a proof of concept at the moment. @khud An actual launcher might be better hosted in the kshell repo itself?

I've fixed the setup instructions already. Also the SNAPSHOT was replaced by using a commit hash for reproducibility until all artifacts are on jcenter/central.

I've moved your comment into a separate ticket #179