-Changed TweetTokenizer to have methods for:
	--getting a tweet from a line of a file (since each one is placed on a
separate line)
	--getting a mention (@) from tweetText
-TweetTokenizer can be easily extended to get tags by adding another
method (I'll do this tomorrow)
-Tester modified to go through the file in data/tweets.log (gathered
from our tweetdata program 2/18/13 around 9pm)
-Added a list of common English words that can be used when determining
if a found word is a stop word.