Stopped WMATweetView from stealing tap gestures when user taps on plain text

The UITapGestureRecognizer that's attached to a WMATweetView steals all taps in the view, even if the user doesn't tap on a link/mention/hashtag. The reason this is a problem is that if you embed the WMATweetView in a table view, the table view cell selection event never gets called. This commit fixes this problem.