title: Vuefity Data Table with select-all event
body: <p>I create one data table with option select-all, in each row in my table I add one event in checkbox</p>
  
  <pre><code>&lt;v-checkbox
          primary
          hide-details
          v-model="props.selected"
          @change="selecionarPedido"
        &gt;&lt;/v-checkbox&gt;
  </code></pre>
  
  <p>So It`s possible to put a event in seletAll checkbox (that checkbox in the header? or an envent in v-checkbox that fire when the select-all change the value?</p>