4.0.0-alpha: Hifitime rewrite

Version 4.0.0-alpha

The main change in this refactoring is that Epochs now keep the time in their own time scales. This greatly simplifies conversion between time scales, and ensures that all computations happen in the same time scale as the initialization time scale, then no sub-nanosecond rounding error could be introduced.

What's Changed

• 4.0.0 dev gh 237 by @gwbres in #289
• Refactor epoch to keep time in its own time scale by @gwbres and @ChristopherRabotin in #280
• Removed der dependency by @ChristopherRabotin in #297
• Refactor epochrs as a module by @ChristopherRabotin in #298
• Duration serde now human readable + Display of Epoch is now Gregorian in its initialization time scale by @ChristopherRabotin in #299
• Improve error handling by @ChristopherRabotin in #300
• Support exceptions in Python by @ChristopherRabotin in #301
• Fix conversion to Gregorian by @ChristopherRabotin in #303
• Add Python regression test for #249 by @ChristopherRabotin in #305
• Breaking change: renamed Julian date constants and removed other Julian date constants by @ChristopherRabotin in #307
• Fix bug in to_gregorian_str by @ChristopherRabotin in #308
• Update pyo3 requirement from 0.21.1 to 0.22.0 by @dependabot in #309
• Revert "Update pyo3 requirement from 0.21.1 to 0.22.0" by @ChristopherRabotin in #310

Full Changelog: 3.10.0...4.0.0-alpha