fixing some text and adding prev actions to reveal

src/qml/presenter/Presentation.qml

@@ -415,6 +415,9 @@ FocusScope {
         function onRevealNext() {
             previewSlide.revealNext();
         }
+        function onRevealPrev() {
+            previewSlide.revealPrev();
+        }
     }
 
     /* Connections { */

src/qml/presenter/PresentationWindow.qml

@@ -89,6 +89,12 @@ Item {
             else
                 presentationSlide.stopAudio();
         }
+        function onRevealNext() {
+            presentationSlide.revealNext();
+        }
+        function onRevealPrev() {
+            presentationSlide.revealPrev();
+        }
     }
 
     function loadVideo() {

src/qml/presenter/Slide.qml

@@ -145,7 +145,7 @@ Item {
             Controls.Label {
                 id: lyrics
                 text: root.text
-                /* text: root.width / textSize */
+                /* text: root.width / 1000 * root.textSize */
                 font.pixelSize: root.width / 1000 * root.textSize 
                 /* minimumPointSize: 5 */
                 fontSizeMode: Text.Fit