Display extended round info

[Forty-Bot]

This includes per-round damage and kills, as well as events such as captures and ubers. In the grand scheme of things, this would result in a round column being added to the primary key in player_stats, with NULL values representing the current, full-game stats (similarly, the round_extra table could be rows in player_stats with NULL steamid64). However, given that the current per-round, per-player info is much less detailed, it can be stored in a separate table (perhaps round_stats?).