Bug fix: if a modal assembly did not contain any constraint, in release mode it threw an a memory access exception (Eigen3 issue).
Bug fix: if a modal assembly did not contain any constraint, in release mode it threw an a memory access exception (Eigen3 issue).

rserban/chrono,rserban/chrono,projectchrono/chrono,projectchrono/chrono,projectchrono/chrono,dariomangoni/chrono,dariomangoni/chrono,rserban/chrono,dariomangoni/chrono,dariomangoni/chrono,rserban/chrono,projectchrono/chrono,projectchrono/chrono,rserban/chrono,dariomangoni/chrono,dariomangoni/chrono,projectchrono/chrono,rserban/chrono,rserban/chrono