Examples: don't set colors as strings

Use the 3-int ctor of QColor instead.

Change-Id: Ib00e3f6c93a153dfdaddde6e72cb6f8f3234fdc4
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

examples/canvas3d/framebuffer/main.cpp

@@ -73,7 +73,7 @@ int main(int argc, char *argv[])
 
     viewer.setTitle(QStringLiteral("Render into FrameBuffer"));
     viewer.setResizeMode(QQuickView::SizeRootObjectToView);
-    viewer.setColor("#f2f2f2");
+    viewer.setColor(QColor(0xf2, 0xf2, 0xf2));
     viewer.show();
 
     return app.exec();

examples/canvas3d/interaction/main.cpp

@@ -73,7 +73,7 @@ int main(int argc, char *argv[])
 
     viewer.setTitle(QStringLiteral("Interaction"));
     viewer.setResizeMode(QQuickView::SizeRootObjectToView);
-    viewer.setColor("#fafafa");
+    viewer.setColor(QColor(0xfa, 0xfa, 0xfa));
     viewer.show();
 
     return app.exec();

examples/canvas3d/textureandlight/main.cpp

@@ -83,7 +83,7 @@ int main(int argc, char *argv[])
 
     viewer.setTitle(QStringLiteral("Textured and Lit Cube"));
     viewer.setResizeMode(QQuickView::SizeRootObjectToView);
-    viewer.setColor("#fafafa");
+    viewer.setColor(QColor(0xfa, 0xfa, 0xfa));
     viewer.show();
 
     return app.exec();