-Stabilization API

-Update leap year function for Solar calendar

-Remove unused code

-Translate comments
-Other

-Improving logic (+ date-cli)

-Fix Rata Die for Julian Calendar

-Implement converter to presentation

-Resolve logical errors

-Getting rid of binding to the Gregorian calendar

-Explicit value typing

-Adding Solar Calendar

-Other improvements

Remove build.rs (cargo not support build.rs to publish in workspace)

Bump version to 1.7.3