LOW PRIO example-project/src/main|test/resources/.gitempty

similar story to https://github.com/svenefftinge/maven-xtext-example/pull/5, but here with a .gitempty instead of a .gitignore, for example-project/src/main + test/resources/ ... again not strictly Maven related - but this just makes checking out this project and not having annoying red errors in the workspace so much nicer.

If you know a better solution for this annoying Eclipse problem - let me know! ;)