title: Arbitrary function on react-leaflet marker click
body: <p>React-leaflet nicely provides the ability to put content within a <code>Popup</code> of a Marker. </p>
  
  <p>For instance in my example:</p>
  
  <pre class="lang-jsx prettyprint-override"><code>            &lt;Marker position={[item.lat, item.lng]} key={item.machineid}&gt;
                &lt;Popup maxWidth={720}&gt;
                  &lt;ItemGrid machineid={item.machineid}
                            username={this.props.username}/&gt;
                &lt;/Popup&gt;
              &lt;/Marker&gt;
  </code></pre>
  
  <p>However if this content is too big, it can be unwieldly, especially on mobile. I would like to have a (bootstrap) Modal interface activate on the click of the Marker. Is there way to do that in react-leaflet?</p>