Zombie/ZombieBase


 * : 1 or 0 (true/false) - true if this zombie is an infected villager. May be absent.
 * : 1 or 0 (true/false) - true if this zombie is a baby. May be absent.
 * : -1 when not being converted back to a villager, positive for the number of ticks until conversion back into a villager. The regeneration effect will parallel this.
 * : 1 or 0 (true/false) - true if the zombie can break doors (default value is 0).
 * : Used to determine what profession the zombie is represented as, as well as what profession it will become when cured.