[Forms] Use ng-model for tree state

Use ng-model when communicating state to/from the
tree in browse mode. This will simplify implementation
of the Locator control, which also uses a tree, but
which should not set navigation state. WTD-593.

platform/commonUI/general/res/templates/tree.html

@@ -1,6 +1,8 @@
 <ul class="tree">
     <li ng-repeat="child in composition">
-        <mct-representation key="'tree-node'" mct-object="child" parameters="parameters">
+        <mct-representation key="'tree-node'"
+                            mct-object="child"
+                            ng-model="ngModel">
         </mct-representation>
     </li>
 </ul>