Starplot

- Added perspective projections (Orthographic, Stereographic) to map plots - many thanks to bathoorn
- Zenith plots are now a type of projection for map plots, to support plotting the Milky Way, constellation borders and more - many thanks to bathoorn
- Removed the visible style property and instead now you control what is plotted by calling functions on the plot (e.g. p.stars(mag=8)) to be more consistent with other plotting frameworks and allow more control over what's plotted and how. For example, now you can do things like plotting very bright stars with a different marker (and sizes, etc) than dimmer stars.
- Optional callables for calculating star size/alpha/color when plotting stars
- Nebula outlines! via OpenNGC
- Stars are now plotted in order of their calculated size, which prevents "bigger" stars from hiding "smaller" stars
- Added more marker symbols and style extensions
- [**v0.9.1**] Fixes bug with plotting moon and planets as their true size

v0.8.x

- Adds new Milky Way outline created from a NASA image, and broken into sections to speed up plotting/exporting
- Adds styling support for more DSO types
- Adds support for Mollweide projection
- Fixes map and optic plots to handle wrapping of RA (e.g. plotting RA extent from 2h -> 18h)
- Fixes a bug in all plots that prevented some star styles to not get applied
- [**v0.8.1**] Fixes a small bug in adjusting RA extent on map plots
- [**v0.8.2**] Fixes a small bug in determining if a RA/DEC is in bounds of a plot
- [**v0.8.3**] More consistent polygon/circle sizing across projections
- [**v0.8.4**] Fixes a small bug in plotting text labels of DSOs, which prevented some styles from getting applied