[Representation] Handle edge cases

Handle edge cases (e.g. directive priorities, race conditions)
to ensure that mct-representation and mct-include display correctly
when added to or removed from the DOM.

platform/representation/src/MCTRepresentation.js

@@ -236,6 +236,9 @@ define(
                 // Handle Angular's linking step
                 link: link,
 
+                // May hide the element, so let other directives act first
+                priority: -1000,
+
                 // Two-way bind key and parameters, get the represented domain
                 // object as "mct-object"
                 scope: {