Omegalib 6.0 released

This is a large release, improving performance and fixing several bugs in the core library, introducing the omega maintenance scripts for easy installing and building omegalib on all platforms, and adding support for dynamic immersive windows both in the core library and through the MVI module. Full release notes here: https://github.com/uic-evl/omegalib/releases/tag/v6.0 Git tag: v6.0