mob casting logic upgrade

src/engine/objects/Mob.java

@@ -91,6 +91,7 @@ public class Mob extends AbstractIntelligenceAgent {
 	private int aggroTargetID = 0;
 	private boolean walkingHome = true;
 	private long lastAttackTime = 0;
+	public long nextCastTime = 0;
 	private long deathTime = 0;
 	private ConcurrentHashMap<Mob, Integer> siegeMinionMap = new ConcurrentHashMap<>(MBServerStatics.CHM_INIT_CAP, MBServerStatics.CHM_LOAD, MBServerStatics.CHM_THREAD_LOW);
 	public ReentrantReadWriteLock minionLock = new ReentrantReadWriteLock();