Moved everything associated with executing and explaining queries to querytab.

It is now possible to create multiple independent query tabs. However
somethings are currently a bit broken.

stopwatch.h

@@ -0,0 +1,24 @@
+#ifndef STOPWATCH_H
+#define STOPWATCH_H
+
+#include <QTimer>
+#include <QElapsedTimer>
+#include <memory>
+
+class StopWatch : public QObject {
+	Q_OBJECT
+public:
+	StopWatch();
+
+	void start();
+	qint64 elapsed();
+private:
+	std::unique_ptr<QElapsedTimer> m_elapsed = nullptr; ///< Keeps time
+	std::unique_ptr<QTimer> m_timer = nullptr; ///< triggers updates
+
+
+private slots:
+	void updateTimer();
+};
+
+#endif // STOPWATCH_H