title: change angular material datePicker icon
body: <p>I wonder if it is possible to change the icon displayed using the datePicker of angular material.</p>
  
  <p>This is the code from the angular material docs.</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;md-input-container&gt;
    &lt;input mdInput [mdDatepicker]="picker" placeholder="Choose a date"&gt;
    &lt;button mdSuffix [mdDatepickerToggle]="picker"&gt;&lt;/button&gt;
  &lt;/md-input-container&gt;
  &lt;md-datepicker #picker&gt;&lt;/md-datepicker&gt;
  </code></pre>
  
  <p>Is there a way to achieve that?</p>