Unescape HTML entities & grab full retweet text

Some simple fixes to prevent html entities like "&amp" from showing up in tweets.

Additionally, the entire text for retweeted statuses is grabbed, so that we don't get ellipses in the middle of the text.
format with `t['text']` is not safe if it contains some non-English character (I tested with Japanese). Instead we should use concatenation here
```python
text = 'RT @' + t['retweeted_status']['user']['screen_name'] + ': ' +\
            t['retweeted_status']['text']
```