Only allow mnlfit to run with 'firth=true' (Jeffreys's prior regularization) for dichotomous logistic regression. Multivariate case needs to be fixed. 
Only allow mnlfit to run with 'firth=true' (Jeffreys's prior regularization) for dichotomous logistic regression. Multivariate case needs to be fixed. 

ckovach/GazeReader,ckovach/GazeReader