title: How to use Image as iconSource in MenuItem
body: <p>I want to add icon to my menu item in QML. Only way that works is to assign qt resource url "qrc://..."  to <code>MenuItem.iconSourse</code></p>
  
  <pre><code>import QtQuick 2.0
  import QtQuick.Controls 1.2       
  MenuItem {
              text: qsTr("Find...")
              iconSource: "qrc:/img/find.png"  // icon show OK
              shortcut:  "Ctrl+F"
          }
  </code></pre>
  
  <p>but i need to get image from plugin resourses. I tried imageprovider, it works well for <code>Image.sourse</code> but for <code>MenuItem</code> doesn't</p>
  
  <pre><code>import QtQuick 2.0
  import QtQuick.Controls 1.2    
  import plugins.spmqml.colorschema 1.0
      ...
              MenuItem {
                  text: qsTr("Find...")
                  iconSource: "image://provider/find.png" // icon doesn't show
                  shortcut:  "Ctrl+F"
              }
  </code></pre>
  
  <p>imageprovider <code>requestImage</code> function not even called.</p>
  
  <p>Is any way to load image from plugin to MenuItem?</p>