Implementation of 'Andrew's Monotone Chain Algorithm' for convex hull construction.
References:
Algorithmist (2011):
Monotone Chain Convex Hull. algorithmist.com.
Andrew, A.M. (1979): Another Efficient Algorithm for Convex Hulls in Two Dimensions. Info. Proc. Letters 9, pp.216-219.
Sunday, D. (2001-2006):
The Convex Hull of a 2D Point Set or Polygon. Softsurfer.com.