Vehicle and trading bugfixes (#51)

* Sanity checks + Starting level changes

- Item movement handler checks to make sure items aren't moved from equipment slot to equipment slot.
- Item give command checks to make sure an out of bounds item is not spawned (Below iType 0 or above iType 8)
- Players now begin at level 36, consequently the item give command does not level you up now.

* Initial Trade Implementation

* Sanity Check

- Prevents out of bounds item movement by comparing it to AINVEN_COUNT.

* Taros and Trading

* Update ItemManager.cpp

* Update ItemManager.cpp

* working trading system

* Trading system code pointerified

- It works with the recent pointer changes needed.

* Vehicles and Trading bugfixes

src/ItemManager.hpp

@@ -16,4 +16,5 @@ namespace ItemManager {
     void itemTradeRegisterItemHandler(CNSocket* sock, CNPacketData* data);
     void itemTradeUnregisterItemHandler(CNSocket* sock, CNPacketData* data);
     void itemTradeRegisterCashHandler(CNSocket* sock, CNPacketData* data);
+    void itemTradeChatHandler(CNSocket* sock, CNPacketData* data);
 }