title: How to make visible both icon and text on QML ToolButton
body: <p>I am creating desktop application using QML and QtQuick.Components. I want to place on the toolbar buttons like the standard MacOS settings dialogs do: <img src="https://i.stack.imgur.com/khQPc.png" alt="Toolbar"></p>
  
  <p>I use ToolBar and <a href="http://qt-project.org/doc/qt-5.1/qtquickcontrols/qml-qtquick-controls1-toolbutton.html" rel="noreferrer">ToolButton</a>, but I can't find the way to do it. For instance with the following code it shows icons only:</p>
  
  <pre><code>ApplicationWindow {
      // ...
  
      toolBar: ToolBar {
          RowLayout {
              ToolButton {
                  text: qsTr("Main")
                  iconSource: "main.png"
              }
              ToolButton {
                  text: qsTr("System")
                  iconSource: "system.png"
              }
              ToolButton {
                  text: qsTr("Items Book")
                  iconSource: "itemsbook.png"
              }
          }
      }
  }
  </code></pre>
  
  <p>And it seems like <a href="https://qt.gitorious.org/qt-components/desktop/source/1777280fe31f86839089d3e3218061a4f28d93b4:components/ToolButton.qml" rel="noreferrer">ToolButton</a> can show either text or icon: </p>
  
  <pre><code>Text {
      id: textitem
      text: button.text
      anchors.centerIn: parent
      visible: button.iconSource == "" // &lt;=========
  }
  </code></pre>