title: How to get the checked items from kendo treeview
body: <p>HTML CODE: </p>
  
  <pre><code>                        &lt;div&gt;
                              &lt;md-button ng-click="getCheckedItems()"&gt;TEST&lt;/md-button&gt;
                          &lt;/div&gt;
                          &lt;div kendo-tree-view="tree"
                               k-data-source="treeData"
                               k-on-change="selectedItem = dataItem"&gt;
  
                              &lt;span k-template&gt;
                                  &lt;md-checkbox !important ng-click='click(dataItem)'&gt;{{ dataItem.text}}&lt;/md-checkbox&gt;
                              &lt;/span&gt;
                          &lt;/div&gt;
  </code></pre>
  
  <p>I want to get the checked items from the treeview and save it as string with ',' between 2 texts using the get function $scope.getCheckedItems = function(){}</p>