Zombie SFX + Tweaks to Infection mechanics
- infected players now make various zombie noises when hit/killed
- zombie's health reduces to #ZombieHealth (set in config) when struck by another player. This makes zombies weaker in hand-to-hand combat, while (relatively) reducing effectiveness of arrows.
- #ZombieHealth increases each minute for the last 5 minutes of a game.
- Infection time limit can now be set in the config file