Merge pull request #235 from JerrySievert/master

add isConvex()
Merge pull request #236 from JerrySievert/master

replace convexHull
recurse arrays for intersection instead
Merge pull request #237 from kenichi/recurse_arrays

recurse arrays for intersection instead
Merge branch 'master' of github.com:Esri/Terraformer
updated to include recursive intersection code