2009-3-5 Yu-Sung Su     <ys463@columbia.edu>  
  * add more examples that use all the type
  * plot the orginal data, not the preprocessed one
  * fix missing.pattern.plot, not pretty
  
  
2009-3-3 Yu-Sung Su     <ys463@columbia.edu>  
  * fix mi.polr                        ## Su: DONE

2009-2-16 Yu-Sung Su     <ys463@columbia.edu>  
  * fix display.lm.mi, display.glm.mi  ## Su: DONE

2009-1-26 Yu-Sung Su     <ys463@columbia.edu>  
  *R/mi.check: auto mi recoding, not yet functional
  *R/plot: plot.categorical need to have right labels
