New camera selection API in QML.

Also added a new QtMultimedia global object which makes it possible
to retrieve the list of available cameras. It can be extended with
new utility functions in the future.

Includes documentation, example and auto tests.

Task-number: QTBUG-23770
Change-Id: Ifea076329c3582ea99246ee1131853344a7b773f
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

examples/multimedia/declarative-camera/VideoCaptureControls.qml

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the examples of the Qt Toolkit.
@@ -39,7 +39,7 @@
 ****************************************************************************/
 
 import QtQuick 2.0
-import QtMultimedia 5.0
+import QtMultimedia 5.4
 
 FocusScope {
     property Camera camera
@@ -53,7 +53,7 @@ FocusScope {
 
     Rectangle {
         id: buttonPaneShadow
-        width: buttonsColumn.width + 16
+        width: bottomColumn.width + 16
         height: parent.height
         anchors.top: parent.top
         anchors.right: parent.right
@@ -105,6 +105,11 @@ FocusScope {
             id: bottomColumn
             spacing: 8
 
+            CameraListButton {
+                model: QtMultimedia.availableCameras
+                onValueChanged: captureControls.camera.deviceId = value
+            }
+
             CameraButton {
                 text: "Switch to Photo"
                 onClicked: captureControls.photoModeSelected()