Add module-info.class for java 9+ JPMS support

[Burtan]

Add module-info.class for java 9+ JPMS support.
For libraries you have to care though, that you need to have to compile the sources with java 8 and the module-info.class with 9+, otherwise you exclude users with java 8.

[hoijui]

If you can come up with a clean way to do exactly what you say with Maven, please make a pull request!
I just tried to find out, and It seems not likely that compiling the bulk with Java 8 but compiling module-info.java with Java 9+ is possible.
Am I wrong?

[Burtan]

I don't know about maven, but with gradle its possible. Would you like to swap the build system? Maybe I can make a pull request for it.

[hoijui]

I don't like gradle. I have seen many projects become fail because of it. It leaves way too much freedom to the devs, for being a build-system.