merge
update01/05/02
Merge branch 'master' of https://github.com/psyclaudeZ/ML14-Project into jingxin

Conflicts:
	Code/data/tweets
	Code/src/tweet_cleaner.pyc
.
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Fixed a bug: incorrect calculation for high/low retweet indicator.
Modifed crawler_celebrity_tweets.py in order to solve the problem of crawlingin correct number of tweets.