Add support for KiCAD 6.99 (VECTOR2I / wxPoint + GetOrientation().AsDegrees())

[Bouni]

This fixes #15 so the plugin works for 6.0 as well as for 6.99

[easyw]

@Bouni sorry for the big delay in my reviewing... Is your PR also compatible with kicad v5? In case of not it would be possible to usehasattr() function to make the tool compatible with v5,6,7?

[Bouni]

This is funny, I attempted to use snap2grid today with the latest 6.99 and realized it doesn't work. So I went and added some fixes to the installed plugin just to relalize that I've submitted a PR to you this summer which I totally forgot about 😅

Actually my PR is not very clean, give me a bit time and I'll cme up with something nicer!

[Bouni]

@easyw I've tested with KiCad 6.0.9 and 6.99.0-5139-g314c813aca, both work as expected. I have no KiCAD 5 installation to test.

[easyw]

thanks