SReachTools now works with CVX v2.2

• Maximum volume ellipsoid option in SReachSetCcO
• SReachSetCcO can now handle non-2D set of direction vectors
• Updated SReachTools.pdf to peer-reviewed copy
• GUROBI abandoned as the preferred CVX backend solver, and instructions for MOSEK included due to issues with CVXv2.2
• SReachSet provides the maximum probability of safety if no set_of_dir_vecs is provided