docs(demo-site): more runnable examples

demo-site/index.html

@@ -88,8 +88,8 @@ <h1>ngTable</h1>
  <li class="active">
  <a href="#btn-dropdowns">x. Grouping</a>
  <ul class="nav">
- <li><a href="#/demo/4-1">Basic example</a></li>
- <li><a href="#/demo/4-2">Grouping with callback</a></li>
+ <li><a href="#/grouping/demo-grouping-basic">Basic example</a></li>
+ <li><a href="#/grouping/demo-grouping-fn">Custom grouping function</a></li>
  <li><a href="#/demo/4-3">Dynamic grouping</a></li>
  </ul>
  </li>

demo-site/views/grouping/demo-grouping-basic.html

@@ -0,0 +1 @@
+<p data-height="810" data-theme-id="17721" data-slug-hash="ojvGaN" data-default-tab="result" data-user="christianacca" class='codepen'>See the Pen <a href='http://codepen.io/christianacca/pen/ojvGaN/'>Grouping - basic example</a> by christianacca (<a href='http://codepen.io/christianacca'>@christianacca</a>) on <a href='http://codepen.io'>CodePen</a>.</p>

demo-site/views/grouping/demo-grouping-fn.html

@@ -0,0 +1 @@
+<p data-height="810" data-theme-id="17721" data-slug-hash="jbNGjx" data-default-tab="result" data-user="christianacca" class='codepen'>See the Pen <a href='http://codepen.io/christianacca/pen/jbNGjx/'>Custom grouping function</a> by christianacca (<a href='http://codepen.io/christianacca'>@christianacca</a>) on <a href='http://codepen.io'>CodePen</a>.</p>