[+] checking ccw contour for convex with tests
[+] checking contour for ccw orientation with tests
[+] convex ccw contour contains point (with tests)
[+] visualization for "checking contour for ccw orientation"
[+] visualization for "checking ccw contour for convex"
[+] visualization for "convex ccw contour contains point"
cosmetic
close #17: merging free0u add-algo