[Layout] Support sub-object selection in layout (#1811)

Updates to sub object selection, first cut of selection APIs.

* [API] Add inspector view registry to register inspector view providers and show a view in the inspector.

[API] Modify the selection API to register the click event and handle the event. The API will add a class to the selected object and the immediate parent of the selected object.

[Directive] Implemenet mct-selectable directive for making an element selectable.

[Layout] Update the layout controller to use the Selection API. Also, add double click gesture to allow drilling into a selected object.

Populate the Elements pool with contained elements of the selected object. Update toolbar and inspector to listen for the changes in selection.

* [Frontend] Mods to markup and CSS for sub-object selection

* MCTSelectable allows selection in initialization, use to select on navigation

[Frontend] Show grid in first nested layout, hide from deeper nesting. Only show grids when applicable to relative selection.

* Fix checkstyle and lint errors

* Bring back the change that made mct-init-select work

* [Inspector] Make sure the right content is displayed based on whether a view provider exists or not.

* Only show table options when editing

* Make reviewers' requested changes

* Fix broken tests

* [Frontend] Cleanups and tweaks

Fixes #1811
- Cleanups between frame, editor and selecting.scss;
- Hover and selected borders visually pumped up a bit;
- Solid borders on hover and selecting when browsing;
- Dashed borders for layouts when editing;
- Fixed cursor to only show move capability when
element is selected;

* [Frontend] Tweaks to frame.no-frame layout

Fixes #1811
- Margin set to 0;
- Overflow set to hidden;

* [Frontend] Fixed position items border width fixed

Fixes #1811
- Set to 1px;

* Add tests for inspector controller and fix broken tests. Clean up code.

* [Fixed Position] Stop event propagation on click handlers in fixed position to avoid the event reaching the selection click handlers which caused issues with toolbar and selection."

* Fix tests

* Add tests

* Add test

* Remove element from document

platform/commonUI/edit/res/templates/edit-object.html

@@ -61,7 +61,12 @@
             <mct-representation key="representation.selected.key"
                                 mct-object="representation.selected.key && domainObject"
                                 class="abs flex-elem grows object-holder-main scroll"
-                                toolbar="toolbar">
+                                toolbar="toolbar"
+                                mct-selectable="{
+                                    item: domainObject.useCapability('adapter'),
+                                    oldItem: domainObject
+                                }"
+                                mct-init-select>
             </mct-representation>
         </div><!--/ l-object-wrapper-inner -->
     </div>

platform/commonUI/edit/res/templates/elements.html

@@ -25,7 +25,7 @@
                  ng-model="filterBy">
     </mct-include>
     <div class="flex-elem grows vscroll">
-        <ul class="tree">
+        <ul class="tree" ng-if="composition.length > 0">
             <li ng-repeat="containedObject in composition | filter:searchElements">
                 <span class="tree-item">
                     <mct-representation
@@ -36,5 +36,6 @@
                 </span>
             </li>
         </ul>
+        <div ng-if="composition.length === 0">No contained elements</div>    
     </div>
 </div>