[Representation] Update documentation

Update documentation of the representation component,
WTD-521.

platform/representation/src/MCTRepresentation.js

@@ -8,9 +8,28 @@ define(
     function () {
         "use strict";
 
+
         /**
+         * Defines the mct-representation directive. This may be used to
+         * present domain objects as HTML (with event wiring), with the
+         * specific representation being mapped to a defined extension
+         * (as defined in either the `representation` category-of-extension,
+         * or the `views` category-of-extension.)
+         *
+         * This directive uses two-way binding for three attributes:
+         *
+         * * `key`, matched against the key of a defined template extension
+         *   in order to determine which actual template to include.
+         * * `mct-object`, populated as `domainObject` in the loaded
+         *   template's scope. This is the domain object being
+         *   represented as HTML by this directive.
+         * * `parameters`, used to communicate display parameters to
+         *   the included template (e.g. title.)
          *
          * @constructor
+         * @param {RepresentationDefinition[]} representations an array of
+         *        representation extensions
+         * @param {ViewDefinition[]} views an array of view extensions
          */
         function MCTRepresentation(representations, views, gestureService, $q, $log) {
             var pathMap = {},