[Fixed Position] Add ability to work in pixel space

Fix code style issues per Victor's review

Add toggle to work in pixel space or grid space, per the issue description.
Each element stores a boolean property that determines whether or not it
snaps to grid space or pixel space. Coordinates are converted between spaces
on toggle, preserving the size of the element in pixels.

To complete: change UI element for toggle to a checkbox.

platform/features/layout/src/elements/TelemetryProxy.js

@@ -21,8 +21,8 @@
  *****************************************************************************/
 
 define(
-    ['./TextProxy','./AccessorMutator'],
-    function (TextProxy,AccessorMutator) {
+    ['./TextProxy'],
+    function (TextProxy) {
 
         // Method names to expose from this proxy
         var HIDE = 'hideTitle', SHOW = 'showTitle';
@@ -39,10 +39,11 @@ define(
          *        configuration
          * @param index the element's index within its array
          * @param {Array} elements the full array of elements
+         * @param {number[]} gridSize the current layout grid size in [x,y] form
          * @augments {platform/features/layout.ElementProxy}
          */
-        function TelemetryProxy(element, index, elements) {
-            var proxy = new TextProxy(element, index, elements);
+        function TelemetryProxy(element, index, elements, gridSize) {
+            var proxy = new TextProxy(element, index, elements, gridSize);
 
             // Toggle the visibility of the title
             function toggle() {