2.0.0 release

[sgillies]

New feature and type hinting. Target date: 2020-06-15.

[dericke]

The last PR I'd like to submit (and then I'll be out of your hair) would be to add read support for MultiGeometry and gx:MultiTrack elements. I should be able to open that PR later today when I get to my other computer. The functional code is done, I just need to finish the tests.

[sgillies]

Sounds good @dericke. I put a date down but am happy to adjust it to your schedule. There's no rush.