logic: Fixed crashes and halting during indexing

* Fixed CPPSqliteException being thrown due to not properly destructed statement in addError
* Fixed indexer getting stuck after building caches because MessageFinishedParsing was interrupted
* removed Message::cancel() method and all related code

bug id = 105

src/lib/utility/messaging/MessageQueue.cpp

@@ -253,11 +253,6 @@ void MessageQueue::sendMessage(std::shared_ptr<MessageBase> message)
 			listener->handleMessageBase(message.get());
 			m_listenersMutex.lock();
 		}
-
-		if (message->cancelled())
-		{
-			break;
-		}
 	}
 }
 
@@ -277,7 +272,7 @@ void MessageQueue::sendMessageAsTask(std::shared_ptr<MessageBase> message, bool
 				[listenerId, message]()
 				{
 					MessageListenerBase* listener = MessageQueue::getInstance()->getListenerById(listenerId);
-					if (listener && !message->cancelled())
+					if (listener)
 					{
 						listener->handleMessageBase(message.get());
 					}