Solarmach

<!-- Release notes generated using configuration in .github/release.yml at v0.1.6 -->

What's Changed

New Features 🎉
* Provide plotting option `long_sector` to color an area in the heliographic plane, either between two Parker spirals or as a cone (6 & 32). [See here for examples.](https://github.com/jgieseler/solarmach/issues/32#issuecomment-1477840946)
* Provide plotting option `background_spirals` to draw a bunch of IMF lines (Parker spirals) in the background (31). [See here for examples.](https://github.com/jgieseler/solarmach/issues/31#issuecomment-1484822581)
* Added [citation](https://github.com/jgieseler/solarmach#citation) to readme

**Full Changelog**: https://github.com/jgieseler/solarmach/compare/v0.1.5...v0.1.6


<!-- Release notes generated using configuration in .github/release.yml at v0.1.5 -->

What's Changed
Bugfixes 🛠
* Fix & add option to define target radius of backmapping (https://github.com/jgieseler/solarmach/pull/25)
* Plot radial distance projected to heliographic equatorial plane instead of radial distance in spherical coordinates (3)
New Features 🎉
* Take into account solar differential rotation (21)


**Full Changelog**: https://github.com/jgieseler/solarmach/compare/v0.1.4...v0.1.5

<!-- Release notes generated using configuration in .github/release.yml at v0.1.4 -->

What's Changed
Bugfixes 🛠
* fix messing up Pandas and matplotlib settings by jgieseler in https://github.com/jgieseler/solarmach/issues/18
New Features 🎉
* make compatible with streamlit by jgieseler in https://github.com/jgieseler/solarmach/pull/19

**Full Changelog**: https://github.com/jgieseler/solarmach/compare/v0.1.3...v0.1.4

- Add `coord_sys` option to the initialization of `SolarMACH` that can be either `'Carrington'`or `'Stonyhurst'`. This sets the used coordinate system for the whole tool. Closes https://github.com/jgieseler/solarmach/issues/1. Replaces the `show_earth_centered_coord` boolean option in `SolarMACH.plot()`
- Add `long_offset` parameter to `SolarMACH.plot()` that defines the longitudinal offset for the polar plot; defines where Earth's longitude is (by default 270, i.e., at "6 o'clock")
- Add `return_plot_object` option to `SolarMACH.plot()`. If set to `True`, the matplotlib figure and axis object are returned, allowing further adjustments to the figure. Closes https://github.com/jgieseler/solarmach/issues/2

- Change file name of example plot in `examples` in order to fix a bug that crashed pip-installing on Windows