title: Font awesome icons in buefy
body: <p>I'm trying to switch my project from <strong>bulma + jQuery</strong> to <strong>buefy</strong>. I load <strong>buefy</strong>, <strong>vue</strong> and <strong>font awesome</strong> from a cdn. <strong>(buefy@0.6.7, vue@2.5.17, font awesome 5.2.0)</strong>. The main problem I have with icons. My project uses font awesome icons. And default buefy iconPack is material design. It must support font awesome. I've tried to change the default icon pack, but that does nothing:</p>
  
  <pre><code>Vue.use(Buefy.default, {
      defaultIconPack: 'fas',
  });
  </code></pre>
  
  <p>the same nothing:</p>
  
  <pre><code>Vue.use(Buefy, {
      defaultIconPack: 'fas',
  });
  </code></pre>
  
  <p>So I need to point the iconpack explicitly for every icon.</p>
  
  <p>The second problem is that even in this case buefy adds <code>fa-lg</code> that I don't need at all. For example for b-tab-item component</p>
  
  <pre><code>&lt;b-tab-item label="Similarity" icon="search" icon-pack="fas"&gt;&lt;/b-tab-item&gt;
  </code></pre>
  
  <p>It renders:</p>
  
  <pre><code>&lt;i class="fas fa fa-search fa-lg"&gt;&lt;/i&gt;
  </code></pre>
  
  <p>Is it possible to change this buefy behaviour?</p>