Added functionality for user generated categories to be used in the word
matching and generated a word_stat object for each category given, based
upon the words in that category. These categories are set in the Categories.txt file.

Hashtag functionality has been fully implemented, with word_stat object
for each unique hashtag generated.

word_stat object now also holds a set of hashtags associated with the word
given for the word_stat object.

From here: The methods presented by both Tweet_Info_Bloc.java and
Word_Stats.java should not change, with all modifications from here being
bug fixes/speed ups unless otherwise noted.