WIP: Figuring out why endpoints aren't found

It seems the approach of turning triangles into Decimals and putting
them into sets is failing for some cases: by plotting fat blue points
at all identified midpoints, we can see that a couple of them are on
edges of the glyph, which should have been thrown out by the algorithm.
Since that isn't working, we'll have to scrap the approach of using sets
and instead use an O(N) search through the identified edge vectors.
WIP: Better endpoint finding

This now finds the endpoints correctly for U+1029 in Padauk font.
WIP: Finding endpoints correctly

This now identifies endpoints correctly for a lot more characters.
I've only tried four so far, but it's gotten it right for all the
characters I've tried. Have to test further, though.