* PowerSet generation is Java and respective unit tests are added
* function name is adjusted to the actual ordering name (Reverse Lexicographical ordering)
* Guava example test function is changed
* LazyLoad powerSet (based on Guava implementation) is added
* set is used instead of map.keySet()
* Lexicographic Order and Gray Order are removed from function names. Unused function (rank and unrank), which are not used in the text, are removed
* PowerSet generation is Java and respective unit tests are added
* function name is adjusted to the actual ordering name (Reverse Lexicographical ordering)
* Guava example test function is changed
* LazyLoad powerSet (based on Guava implementation) is added
* set is used instead of map.keySet()