Convex hull of a Path

[fryguybob]

It shouldn't be too hard to generate a new path that is the convex hull of a given path. In a way this is a stepping stone toward boolean operations on polygons. As a first pass we might consider just Linear segments, but Cubic and arc segments shouldn't be difficult. For Cubic segments splitting on curvature inflection points should remove any lines that would need to be introduced inside a segment.

I'm sure there is a lot of literature on this one that could be tracked down.

[byorgey]

#226 says it closes this issue but I am leaving it open. As far as I can tell #226 only implements the convex hull of a list of points. That is a step in the right direction, but the idea here is to have the convex hull of a Path, which is a bit harder if the path contains any curved segments.