KiCAD 8.0 Compatibility

This release brings the plugin to KiCAD 8, and also includes a lot of small bugfixes.

Thanks to @OfficialDyray @hruger @Anemograph @ferris @i404788 and others who helped, we couldn't have figured this out without you.

Initial Release

First release!

This doesn't yet support zones; open an issue if you need them.