cleaned up the ChSystemFsi and added comments
cleaned up the ChSystemFsi and added comments

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