added EnergySaver intended to handle shutdown.

Moved timer from MouseEventSpy to EnergySaver.
Connected MouseEventSpy and MusicController to EnergySaver.

LenaPi/EnergySaver.cpp

@@ -0,0 +1,60 @@
+#include "EnergySaver.h"
+
+#include <QDebug>
+
+EnergySaver::EnergySaver(QObject *parent) : QObject(parent)
+{
+
+}
+
+void EnergySaver::init(int interval)
+{
+    EnergySaver* saver = instance();
+    saver->initTimer(interval);
+    saver->restartTimer();
+}
+
+
+/**
+ * @brief Implements the singleton pattern.
+ * @return Instance
+ *
+ * If no instance has been created yet, create new instance.
+ */
+EnergySaver *EnergySaver::instance()
+{
+    static EnergySaver* inst;
+    if (inst == nullptr)
+    {
+        inst = new EnergySaver();
+    }
+    return inst;
+}
+
+void EnergySaver::restartTimer()
+{
+    if(mTimer.isActive()){
+        mTimer.stop();
+    }
+    mTimer.start();
+}
+
+/**
+ * @brief Initialize and connect timer.
+ * @param interval Timeout interval in millisecond.
+ */
+void EnergySaver::initTimer(int interval)
+{
+    connect(&mTimer, &QTimer::timeout, this, &EnergySaver::onTimeout);
+    mTimer.setInterval(interval);
+    mTimer.setSingleShot(true);
+}
+
+/**
+ * @brief Behavior on timeout: shut down RaspberryPi.
+ * @todo Call shutdown script.
+ */
+void EnergySaver::onTimeout()
+{
+    qDebug() << "shutting down.";
+}