Core/DBLayer:

- Implement DatabaseWorkerPool::DirectCommitTransaction for synchronous transaction execution (as opposed to asynchronous/enqueued).
- Add MySQL errno 1213 "Deadlock found when trying to get lock; try restarting transaction" handler. If 1213 is called the core will retry to directly execute the transaction a maximum of 5 times.

src/server/shared/Database/MySQLConnection.h

@@ -18,6 +18,7 @@
 #include <ace/Activation_Queue.h>
 
 #include "DatabaseWorkerPool.h"
+#include "Transaction.h"
 #include "Util.h"
 
 #ifndef _MYSQLCONNECTION_H
@@ -91,10 +92,13 @@ class MySQLConnection
         void BeginTransaction();
         void RollbackTransaction();
         void CommitTransaction();
+        bool ExecuteTransaction(SQLTransaction& transaction);
 
         operator bool () const { return m_Mysql != NULL; }
         void Ping() { mysql_ping(m_Mysql); }
 
+        uint32 GetLastError() { return mysql_errno(m_Mysql); }
+
     protected:
         bool LockIfReady()
         {