1.0
* First official release
1.1
* Added in the output percentage of rows in each category and warning if the percentage is too small or large for one category
* The function manual also includes some suggestion on this topic
1.2
* Fixed a problem in the NAMESPACE file
1.3 
* Added the "max" summarization function according to reviewer's advice. It may give a better result for some datasets.
1.4
* The summarization function now uses "pca" method as default