title: How to customise multi filtering with 'mixitup' plugin?
body: <p>I'm using the jQuery plugin <a href="http://mixitup.io/" rel="nofollow">MixItUp</a> to get some filtering on a list of content I have.</p>
  
  <p>The plugin offers a multiFilter out of the box, but the problem is that it has everything showing, and then when you click one of the filters, it removes it from the list, whereas I want it so that when you select one of the filters, it only shows that one. If you click another, it also shows content for that.  <a href="http://mixitup.io/demos/parks" rel="nofollow">There's a demo</a> that has something similar to what I want, but it's more complex than I need - it has two categories for filters, I just need one.</p>
  
  <p>In the demo, they don't use the 'multiFilter' option.  Instead, they seem define the string for the 'filter' option and then spit that out depending on what filter has been clicked.  I did try deconstructing what they had done and reworking it how I wanted, but failed to really get anywhere.</p>
  
  <p>Basically I'm lost, so hoping someone has played with this plugin before.  I just want a kick in the right direction.  Do I need to write a custom click function and forget using the multiFilter, trying to set the filter string, or can the default multiFilter be customised?</p>
  
  <p><a href="http://jsfiddle.net/davidpauljunior/QtQnB/" rel="nofollow">There's a fiddle here with the plugin js added and the default multiFilter functionality</a></p>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;div id="filter"&gt;
      &lt;span&gt;Filter&lt;/span&gt;
      &lt;ul class="filter-list"&gt;
          &lt;li data-filter="all" class="filter active"&gt;&lt;a href="#"&gt;All&lt;/a&gt;&lt;/li&gt;
          &lt;li data-filter="lemon" class="filter"&gt;&lt;a href="#"&gt;Lemon&lt;/a&gt;&lt;/li&gt;
          &lt;li data-filter="orange" class="filter"&gt;&lt;a href="#"&gt;Orange&lt;/a&gt;&lt;/li&gt;
          &lt;li data-filter="apple" class="filter"&gt;&lt;a href="#"&gt;Apple&lt;/a&gt;&lt;/li&gt;
      &lt;/ul&gt;
  &lt;/div&gt;
  
  &lt;ul id="grid"&gt;
      &lt;li class="mix lemon"&gt;
          &lt;h3&gt;Lemon&lt;/h3&gt;
          &lt;p&gt;Some text here&lt;/p&gt;
      &lt;/li&gt;
      &lt;li class="mix orange"&gt;
          &lt;h3&gt;Orange&lt;/h3&gt;
          &lt;p&gt;Some text here&lt;/p&gt;
      &lt;/li&gt;
      &lt;li class="mix apple"&gt;
          &lt;h3&gt;Apple&lt;/h3&gt;
          &lt;p&gt;Some text here&lt;/p&gt;
      &lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p><strong>JS</strong></p>
  
  <pre><code>$('#grid').mixitup({
      multiFilter: 'true',
      showOnLoad: 'lemon orange apple'
  });
  </code></pre>