connected stop, previous and next button;

STILL MISSING: check whether there is a next/previous medium and only
then show/enable buttons

LenaPi/models/MusicModel.cpp

@@ -49,6 +49,24 @@ void MusicModel::playPause()
         emit pause();
 }
 
+void MusicModel::stopMusic()
+{
+    if(mIsPlaying){
+        mIsPlaying = false;
+        emit stop();
+    }
+}
+
+void MusicModel::playNext()
+{
+    emit next();
+}
+
+void MusicModel::playPrevious()
+{
+    emit previous();
+}
+
 NavigationItemModel *MusicModel::getCurrentItem()
 {
     return mCurrentItem;