Initial release of the standalone library
This is the inaugural release of a standalone HPack library for Crystal. It is versioned at 0.9.0 because it really should just go to 1.0.0, but I want to get a little real-world testing of the refactored version in a standalone HTTP2 client library that is coming soon to a GitHub repo near you.
Expect this to bump to 1.0.0 soon.