title: Check for the presence of a sub-list
body: <p>Can you provide me a performing (possibly idiomatic) way to check if a list <code>A</code> is a sublist of a given list <code>B</code>?</p>
  
  <p>E.g.</p>
  
  <pre><code>isSubList(List(1,2), List(1,2,3,4)) // =&gt; true
  isSubList(List(1,2), List(5,6,7,8)) // =&gt; false 
  </code></pre>