Corrected some usage of QueueTask that was already broken as QueueTask is defunct.

core/ExplainTreeModelItem.cpp

@@ -4,6 +4,14 @@
 
 namespace {
 
+	class registerMetaTypes {
+	public:
+		registerMetaTypes()
+		{
+			qRegisterMetaType<ExplainRoot::SPtr>();
+		}
+	} registerMetaTypes_instance;
+
 	ExplainTreeModelItemPtr createPlanItemFromJson(Json::Value &plan)
 	{
 

core/ExplainTreeModelItem.h

@@ -1,9 +1,9 @@
 #pragma once
 
 #include <QList>
-//#include <QVariant>
 #include <vector>
 #include <memory>
+#include <QMetaType>
 
 namespace Json {
 
@@ -161,3 +161,4 @@ public:
 
 };
 
+Q_DECLARE_METATYPE(ExplainRoot::SPtr);