Sacf

Rename from GACF->SACF in line with paper convention. Version bumped to 2.0 as lo longer compatible with previous versions whatsoever.

Including the new squared fractional weight function, authored by LKreutzer.

What's Changed
* Add squared fractional weight function by LKreutzer in https://github.com/joshbriegal/gacf/pull/22

New Contributors
* LKreutzer made their first contribution in https://github.com/joshbriegal/gacf/pull/22

**Full Changelog**: https://github.com/joshbriegal/gacf/compare/v1.0.1...v1.1

Update documentation, minor bugfixes.

First Release of GACF library.

See Readme.md for details.

Similar to astropy.LombScargle class definition.

Clean up build for PyPI release.

C++ and Python codebase. Includes examples of how to generate periods from the G-ACF