Improved the function cpNb3Sn_Arp_Knapp_mat.m: 1) it now works when Tc, Tc0, Tcs are either scalars or vectors. 2) if Tc, Tc0, and Tcs are all vectors with identical elements. If so, they'll be changed to scalars to speed up calculation. 3) Small speed improvement by commenting redundant "ps(idxAboveTc) = 0;". 4) changed code reformatting to make it more readable. NOTE: The edited function is expected to return the same values as before (when Tc, Tc0, Tcs are scalars).