Please add release tags

[shumash]

Kudos on amazing work that's spearheaded so much research!

This repo is still widely used for research, and to facilitate it our library, NVIDIA Kaolin, has been providing camera converters from your conventions to ours and back here. However, recent changes to your repository are not backward compatible, and the lack of tagged versions makes it impossible for us to maintain converters that the community can rely on.

Please consider adding release tags. For example, tag the previous stable version that much of the community has built on, and tag new improvements when stable as well.

As a minor point, it would be great if you enabled pip install of your codebase.