Update the manual section on ChSystem, to explain ChSystemNSC and ChSystemSMC
Update the manual section on ChSystem, to explain ChSystemNSC and ChSystemSMC

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