Leaderboard 2.0 improvements

[bdecato]

• Merge entries that are identical except for case ("C" and "c" should be merged)

• Merge entries that are identical except for a leading hashtag (#ChIPS vs ChIPS) and display them with no hashtag.

• Remove users from the "Thing leaderboard." Currently it displays @wrideout as having 4 points there, because often people delete the mention link and then double-increment him. I think the default behavior here should be to only count a user in the users column, and only count an increment/decrement if it @'s them in the message. Open to opinions on this.

[bdecato]

On second thought, it probably makes more sense to do some of the above as early as possible, probably during the increment/decrement functions. These sanitization issues are already mentioned in #5. Let's think about which make sense to do immediately vs at the leaderboard stage.

[bdecato]

• Sort ties by the number of pluses, not alphabetically!