phi_lam changed to psi_lam (consistent w/ derivations), and other minor changes
dimensions for B1, B3, B4 and phi_lam corrected
dimensions for B1 and B3 corrected
n_str error corrected
initial check-in of solid constitutive model for mixture theory formulation
a more general way of retriving C matrices from moduli, some editing
some editing
B3 modified, some editing
added external force BC contribution to the force used in NtF calculation
MF_dMatrixT changed to MFGP_ToolsT
