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.
According to [Cpython's html.parser warning](https://github.com/python/cpython/blob/master/Lib/html/parser.py#L547),
we should use html.unescape() instead