Provide moment conditions for Mean/StdDev GMM estimation
[m,e] = gmmMsdM(b,gmmopt,Y,X,Z,W)
b = parameter vector fed to function
gmmopt = gmm options tlist
Y = "dependent" variables
X = "independent" variables
Z = instruments (can be same as X)
m = vector of moment conditions
e = model errors (Nobs x Neq)