feat: add support for jpms

[sgammon]

Summary

Adds a module-info.java so that Geantyref can be used from Modular Java apps.

Fixes and closes leangen/geantyref#28 and leangen/geantyref#26

Changelog

• chore: add mvn build wrapper
• chore: add compile run and srcroot for java9
• chore: add java9-compliant implementations where needed
• chore: add mrjar output
• chore: remove Automatic-Module-Name