[Tree] Show top-level node of tree, except root

Show top-level nodes when instantiating tree views, except for
the Root object. Supports Add dialogs in WTD-922.

platform/commonUI/general/bundle.json

@@ -150,12 +150,17 @@
         "representations": [
             {
                 "key": "tree",
-                "templateUrl": "templates/tree.html",
+                "templateUrl": "templates/subtree.html",
+                "uses": [ "composition" ],
                 "type": "root",
                 "priority": "preferred"
             },
             {
                 "key": "tree",
+                "templateUrl": "templates/tree.html"
+            },
+            {
+                "key": "subtree",
                 "templateUrl": "templates/subtree.html",
                 "uses": [ "composition" ]
             },

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

@@ -17,7 +17,7 @@
               ng-show="toggle.isActive()"
               ng-if="model.composition !== undefined">
 
-            <mct-representation key="'tree'"
+            <mct-representation key="'subtree'"
                                 ng-model="ngModel"
                                 mct-object="treeNode.hasBeenExpanded() && domainObject">
             </mct-representation>

platform/core/bundle.json

@@ -115,6 +115,11 @@
                     }
                 ]
             },
+            {
+                "key": "root",
+                "name": "Root",
+                "glyph": "F"
+            },
             {
                 "key": "folder",
                 "name": "Folder",

platform/representation/src/MCTRepresentation.js

@@ -37,7 +37,7 @@ define(
 
             // Assemble all representations and views
             // The distinction between views and representations is
-            // not important her (view is-a representation)
+            // not important here (view is-a representation)
             representations.concat(views).forEach(function (representation) {
                 var key = representation.key;
 
@@ -78,8 +78,8 @@ define(
                 // Populate scope with any capabilities indicated by the
                 // representation's extension definition
                 function refreshCapabilities() {
-                    var representation = representationMap[$scope.key],
-                        domainObject = $scope.domainObject,
+                    var domainObject = $scope.domainObject,
+                        representation = lookup($scope.key, domainObject),
                         uses = ((representation || {}).uses || []);
 
                     if (domainObject) {