Move assets migration to a task. Needs threading.

logic/assets/AssetsMigrateTask.h

@@ -0,0 +1,18 @@
+#pragma once
+#include "logic/tasks/Task.h"
+#include <QMessageBox>
+#include <QNetworkReply>
+#include <memory>
+
+class AssetsMigrateTask : public Task
+{
+	Q_OBJECT
+public:
+	explicit AssetsMigrateTask(int expected, QObject* parent=0);
+
+protected:
+	virtual void executeTask();
+
+private:
+	int m_expected;
+};