Fix title coloring in some examples

examples/animatedbackground/SlideDeck.qml

@@ -44,7 +44,7 @@ Presentation {
 
     BackgroundSwirls {}
 
-    property color textColor: "white"
+    textColor: "white"
 
     Slide {
         centeredText: "Animated Background"

examples/customtransition/OpacityTransitionPresentation.qml

@@ -44,7 +44,7 @@ Presentation {
     width: 1280
     height: 720
 
-    property color textColor: "white"
+    textColor: "white"
 
     property bool inTransition: false;
 

examples/notes/SlideDeck.qml

@@ -19,7 +19,7 @@ Presentation {
     Clock { textColor: "white" }
     SlideCounter { textColor: "white" }
 
-    property string titleColor: "white"
+    titleColor: "white"
 
     showNotes: true
 

src/Presentation.qml

@@ -45,7 +45,7 @@ Item {
 
     property bool showNotes: false;
 
-    property color titleColor: "black"
+    property color titleColor: textColor;
     property color textColor: "black"
     property string fontFamily: "Helvetica"
     property string codeFontFamily: "Courier New"