[MATH-749] Remove GrahamScan, GiftWrap, make MonotoneChain more robust wrt collinear points, add ConvergenceException in case the specified tolerance results in a non-convex hull.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1568752 13f79535-47bb-0310-9956-ffa450edef68