Fixes to ChConvexHull.
Fixes to ChConvexHull.

- ensure proper treatment of some degenerate cases with all points colinear
- fix area calculation (missing 0.5 factor)

Milad-Rakhsha/chrono,projectchrono/chrono,armanpazouki/chrono,armanpazouki/chrono,projectchrono/chrono,Milad-Rakhsha/chrono,rserban/chrono,rserban/chrono,amelmquist/chrono,rserban/chrono,projectchrono/chrono,Milad-Rakhsha/chrono,armanpazouki/chrono,amelmquist/chrono,dariomangoni/chrono,Milad-Rakhsha/chrono,amelmquist/chrono,rserban/chrono,Milad-Rakhsha/chrono,rserban/chrono,armanpazouki/chrono,amelmquist/chrono,dariomangoni/chrono,projectchrono/chrono,amelmquist/chrono,rserban/chrono,amelmquist/chrono,armanpazouki/chrono,dariomangoni/chrono,projectchrono/chrono,armanpazouki/chrono,dariomangoni/chrono,rserban/chrono,dariomangoni/chrono,projectchrono/chrono,dariomangoni/chrono,Milad-Rakhsha/chrono