title: Split rangy range into two at specific offset
body: <p>Ok, have been breaking my head on this one for the last few hours and hope there is somebody here with more experience with the rangy library. Let's say I have the following html:</p>
  
  <pre><code>&lt;p&gt;Lorem Ipsum&lt;note&gt;that's latin&lt;/note&gt; is a placeholder text&lt;/p&gt;
  &lt;p&gt;It is often used in graphic design&lt;note&gt;some other note&lt;/note&gt;&lt;/p&gt;
  </code></pre>
  
  <p>And we've got a selection as indicated by the { and } characters:</p>
  
  <pre><code>&lt;p&gt;Lorem {Ipsum&lt;note&gt;that's latin&lt;/note&gt; is a placeholder text&lt;/p&gt;
  &lt;p&gt;It is often used in graphic design&lt;note&gt;some other note&lt;/note&gt;.}&lt;/p&gt;
  </code></pre>
  
  <p>How could you split up the range into 3 range objects like this:</p>
  
  <ol>
  <li><code>Ipsum</code></li>
  <li><code>is a placeholder text&lt;/p&gt;&lt;p&gt;It is often used in graphic design</code></li>
  <li><code>.</code></li>
  </ol>
  
  <p>With the goal being to exclude a set of elements, in this case being <code>['note']</code>. I don't require a fully functional solution, <strong>all I am looking for is a way to 'split' a rangy range up at a certain point in the range</strong>.</p>