Game flow--countdown, rounds, winner, play again

When the game starts, there should be a countdown and a fight message (tekken/SF style). We can use programmer art for now and ask our artists to make something. This (first round start) should happen automatically when the combat room loads--after #54 is implemented, it will load the combat room when characters are selected.

We also need to register a round end when a player's health hits 0 and then reset characters for the next round

When a player wins 2 rounds, their should be some kind of victory screen (can be programmer art for now) and an option to play again, which will eventually return us to the character select (#54)