Abstract channel schedulers + Mob animation track + More portal SFX

Implemented an improved scheduler system for channels, on where Runnables objects are "registered in" to run on a scheduled future time (effective run time will depend on the proc time of the worker acting under-the-hood).
Implemented a channel scheduler for detecting "mobs currently on animation state". This allows the server to send info to the client about whether a mob should cast a skill or not at that moment.
Improved concurrent protection on MapleMonster listeners registry.
Improved resource deallocation when destroying a monster object.
Added a server flag to allow clean slates to be used on equipments even on the "only successfully used scroll slots" case.
Fixed a critical deadlock case with MapleServerHandler.
Added the portal SFX for many scripted portals that still lacked the sound effect.

src/server/life/MapleMonsterInformationProvider.java

@@ -54,6 +54,7 @@ public class MapleMonsterInformationProvider {
         private final Set<Integer> hasNoMultiEquipDrops = new HashSet<>();
         private final Map<Integer, List<MonsterDropEntry>> extraMultiEquipDrops = new HashMap<>();
         
+        private final Map<Pair<Integer, Integer>, Integer> mobAttackAnimationTime = new HashMap<>();
         private final Map<Pair<Integer, Integer>, Integer> mobSkillAnimationTime = new HashMap<>();
 
 	protected MapleMonsterInformationProvider() {
@@ -226,6 +227,15 @@ public class MapleMonsterInformationProvider {
 		return ret;
 	}
         
+        public final void setMobAttackAnimationTime(int monsterId, int attackPos, int animationTime) {
+                mobAttackAnimationTime.put(new Pair<>(monsterId, attackPos), animationTime);
+        }
+        
+        public final Integer getMobAttackAnimationTime(int monsterId, int attackPos) {
+                Integer time = mobAttackAnimationTime.get(new Pair<>(monsterId, attackPos));
+                return time == null ? 0 : time;
+        }
+        
         public final void setMobSkillAnimationTime(int monsterId, int skillPos, int animationTime) {
                 mobSkillAnimationTime.put(new Pair<>(monsterId, skillPos), animationTime);
         }