get12TermModel

      get12TermModel     Constructs the 12-Term error model (with optional isolation
                         measurement), using measured SOLT data and listed SOLT data.
          get12TermModel(G1,Gm1,G2,Gm2,T,Tm)
          input:
              G1,G2: [3,num_pts] listed (G) and measured (Gm) reflection coefficients
                  of standards used on port 1 and 2 respectively. Standards used in
                  G,Gm must be in same order (ie. G = [O,S,L] Gm = [Om,Sm,Lm])
              T,Tm: [2,2,num_pts] listed (T) and measured (Tm) relfection coefficients
                  of thru standard
              isolation (optional): [2,2,num_pts] measured S-parameters of an isolation measurement.
                  ie. matched loads on each port
          output:
              fwd_terms: [6,num_pts] [e00;e11;e10e01;e10e32;e22;e30]
              rev_terms: [6,num_pts] [ep33;ep22;ep23ep32;ep23ep01;ep11;ep03]