Experimental Character/Client Closure + Morph & Crash skills patch

Player Trade is now enabled inside PQ & events.
Refactored minigame code, now using enums rather than strings for logistics.
Fixed Transformations not applying stat buffs properly.
Warrior's Crash skills now acts accordingly with their description (rather than applying all combined debuffs).
Added a server flag for Crash skills, to apply mob immunity debuffs as well.
Fixed Shark Wave not stacking charges.
Dragon Roar now properly stuns the mobs (stun effect won't show up, though).
Refactored empty method on MapleCharacter, now freeing more resources.
[EXPERIMENTAL] Upon lifetime's end of the object, empty function will be called alongside MapleClient's clear, should issues arise from that, it's TBD.

src/constants/skills/ThunderBreaker.java

@@ -38,4 +38,5 @@ public class ThunderBreaker {
     public static final int TRANSFORMATION = 15111002;
     public static final int SPEED_INFUSION = 15111005;
     public static final int SPARK = 15111006;
+    public static final int SHARK_WAVE = 15111007;
 }