upgrade to delaunator@3

[Fil]

fixes #50

Demos:

• https://observablehq.com/d/c6fd1c17207e5cf6
• https://observablehq.com/d/0f4a4cc6afcc02c3

I had to disable the tests for outeredges, because I'm not using the same outeredges (but they do point to the same nodes).(fixed, see below)

[Fil]

I've now restored the outedges as they used to be; in the following schema:

hull[i-1] -in-> p --> hull[i+1] -out-> hull[i+2]

the outeredge for p = hull[i] is the inedge for hull[i+2]

But this is imho too complicated for what we want (to be able to compute the last neighbor of p when p is on the hull). We can do so with a much more readable hullIndex (see branch hullIndex and specifically cf26755).

So I'd be in favor of removing delaunay.outedges from the API and using hullIndex instead.

In any event, it's a major version change because delaunay.hull is not the linked chain of objects.

[Fil]

superseded by #60