Switch database mutex to recursive because we copy it everywhere

... and I have no idea if any of the calls are re-entrant. yay.

zone/main.cpp

@@ -246,7 +246,7 @@ int main(int argc, char **argv)
 		// when database and content_db share the same underlying mysql connection
 		// it needs to be protected by a shared mutex otherwise we produce concurrency issues
 		// when database actions are occurring in different threads
-		std::shared_ptr<std::mutex> sharedMutex = std::make_shared<std::mutex>();
+		std::shared_ptr<DBcore::Mutex> sharedMutex = std::make_shared<DBcore::Mutex>();
 		database.SetMutex(sharedMutex);
 		content_db.SetMutex(sharedMutex);
 	}