Add SelectEvent to Select interaction

Fixes

examples/select-features.html

@@ -35,6 +35,7 @@
           <h4 id="title">Select features example</h4>
           <p id="shortdesc">Example of using the Select interaction. Choose between <code>Single-click</code>, <code>Click</code> and <code>Hover</code> as the event type for selection in the combobox below. When using <code>Single-click</code> or <code>Click</code> you can hold do <code>Shift</code> key to toggle the feature in the selection.</p>
           <p>Note: when <code>Single-click</code> is used double-clicks won't select features. This in contrast to <code>Click</code>, where a double-click will both select the feature and zoom the map (because of the <code>DoubleClickZoom</code> interaction). Note that <code>Single-click</code> is less responsive than <code>Click</code> because of the delay it uses to detect double-clicks.</p>
+          <p>In this example, a listener is registered for the Select interaction's <code>select</code> event in order to update the selection status below.
           <form class="form-inline">
             <label>Action type &nbsp;</label>
               <select id="type">
@@ -43,6 +44,7 @@
                 <option value="click">Click</option>
                 <option value="pointermove">Hover</option>
               </select>
+              <span id="status">&nbsp;0 selected features</span>
           </form>
           <div id="docs">
             <p>See the <a href="select-features.js" target="_blank">select-features.js source</a> to see how this is done.</p>