Zombie/ZombieBase


 * : 1 or 0 (true/false) - true if this zombie is a baby. May be absent.
 * : 1 or 0 (true/false) - true if the zombie can break doors (default value is 0).
 * : For a non-drowned zombie, the number of ticks until it converts to a drowned. (default value is -1, when no conversion is under way).