TPolygon2::SimplifyDouglasPeucker

Polygon simplification code adapted from: [http://softsurfer.com/Archive/algorithm_0205/algorithm_0205.htm](http://softsurfer.com/Archive/algorithm_0205/algorithm_0205.htm) simplifyDP(): This is the Douglas-Peucker recursive simplification routine It just marks Vertices that are part of the simplified polyline for approximating the polyline subchain v[j] to v[k].