FreezeTowers now slow down players too.
This code is unused
Zombies are now less likely to break down buildings to get to a target.
HealthBar now extends Particle.
They can be used the old way by drawing the healthbar manually or you can add it to the ParticleController. All buildings now use the Particle version of HealthBar.
Uses percent of speed to determine frozen speed.
Projectile's sound is now loaded at the beginning instead of the first shot.