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/net/MapleServerHandler.java

@@ -189,10 +189,12 @@ public class MapleServerHandler extends IoHandlerAdapter {
     
     private void registerIdleSession(MapleClient c) {
         if(idleLock.tryLock()) {
-            idleSessions.put(c, System.currentTimeMillis());
-            c.announce(MaplePacketCreator.getPing());
-            
-            idleLock.unlock();
+            try {
+                idleSessions.put(c, System.currentTimeMillis());
+                c.announce(MaplePacketCreator.getPing());
+            } finally {
+                idleLock.unlock();
+            }
         } else {
             tempLock.lock();
             try {