updated documentation

Included suggestions from #58.

docs/index.html

@@ -2841,7 +2841,9 @@ <h4 id="options-parameter">options parameter</h4>
 </li>
 <li><p><code>size</code>
 <em>(Type: <code>string</code>, Example: <code>lg</code>)</em> -
-Optional suffix of modal window class. The value used is appended to the <code>modal-</code> class, i.e. a value of <code>sm</code> gives <code>modal-sm</code>.</p>
+Optional suffix of modal window class. The value used is appended to the <code>modal-</code> class, i.e. a value of <code>sm</code> gives <code>modal-sm</code>. 
+(<i>Note: Since this is directly injected into the class for the modal, you can leverage additional Bootstrap modal classes, such as <code>modal-dialog-centered</code>.
+Ex: <code>md modal-dialog-centered</code>.</i>)</p>
 </li>
 <li><p><code>template</code>
 <em>(Type: <code>string</code>)</em> -