- added isEmpty() method in FPTree
- fixed memory issue in removal of infreq path items caused due to deletion of path item before getting next path node
- more and more testing
Major
- implemented functionality for printing out all frequent item sets given a single path tree

- added getSinglePath in FPTree, which returns a vector of string item sets
- added getSize() method in HeaderItem List - (can be optimized by keeping a count)
- HeaderTable print() method now prints domain item's count