2014-10-13: 
  Simplified some namespace dependencies. Eliminated useless pseudo-R-squared statistics 
  form getSummary.mclogit

2014-08-23:
  Added 'anova' methods

2014-03-10:
  Refactored code -- algorithms should be more transparent and robust now (hopefully!).
  mclogit without and with random effects can handle missing values now.
  Fixed predict method -- use of napredict; handles single indep-variable situation now.
  Fixed embarassing typo -- prior weights do work now (again?). 
  Included AIC and BIC methods contributed by Nic Elliot <nic_elliot@yahoo.co.uk>
