not supported edge cases

[Armano]

i found few edge cases,

when points provided to Delaunay are on one line (x or y axis) delaunay is not able to produce correct result, and it throwing error with

Error: No Delaunay triangulation exists for this input.

that's a case even no matter how many points there in single line.
this was not a case with d3-voronoi

points

[20,0,107.24319391634981,0,188.8577946768061,0,275.9837262357414,0,360.4126235741445,0,447.6558174904943,0,532.0847148288974,0,619.3279087452472,0,706.5711026615969,0,791,0]

[Mike Bostock]

Duplicate of #20.