Allow "islandora_object" entities to be loaded.

Should allow objects to be loaded in Rules, by specifying the "id" as
a property. (trying to load by "id" directly is not possibly, since Rules
assumes that IDs are numeric)

includes/object.entity_controller.inc

@@ -29,9 +29,13 @@ class IslandoraObjectEntityController implements DrupalEntityControllerInterface
    *   An array of loaded objects.
    */
   public function load($ids = array(), $conditions = array()) {
-    if (!empty($conditions)) {
+    if (isset($conditions['id'])) {
-      // TODO: Allow loading by specifying IDs in the condition.
+      // Allow loading by specifying the ID as a property as a work-around,
-      throw new Exception('Conditions not implemented.');
+      // since some components dealing with entities expect IDs to be numeric.
+      $ids = array_merge($ids, (array) $conditions['id']);
+    }
+    elseif (!empty($conditions)) {
+      throw new Exception('Conditions other than "id" not implemented.');
     }
 
     $loaded = array();