Added some classes from a stackoverflow to utilize Qt's concurrency functions especially cancellable QFuture's

core/TaskControl.h

@@ -0,0 +1,19 @@
+#ifndef TASKCONTROL_H
+#define TASKCONTROL_H
+/** From answer by Hatter
+ *
+ * https://stackoverflow.com/questions/5423058/qfuture-that-can-be-cancelled-and-report-progress
+ */
+
+#include <QFutureInterfaceBase>
+
+class TaskControl
+{
+public:
+	TaskControl(QFutureInterfaceBase *f) : fu(f) {  }
+	bool shouldRun() const { return !fu->isCanceled(); }
+private:
+	QFutureInterfaceBase *fu;
+};
+
+#endif // TASKCONTROL_H