[Imagery] Begin adding mct-image

Begin adding directive to preload images before displaying
them, to avoid flashing of imagery as it arrives. WTD-1170.

platform/features/imagery/res/templates/imagery.html

@@ -30,7 +30,12 @@
             class="l-image-main s-image-main"
             ng-class="{ paused: imagery.paused(), stale:false }"
             style="background-image:url('{{imagery.getImageUrl()}}');"
-            ></div>
+            >
+        </div>
+        <mct-image class="l-image-main s-image-main"
+                   ng-class="{ paused: imagery.paused(), stale: false }"
+                   src="imagery.getImageUrl()">
+        </mct-image>
         <div class="l-image-main-controlbar bar">
             <div class="left">
                 <a

platform/features/imagery/src/directives/MCTImage.js

@@ -0,0 +1,53 @@
+/*****************************************************************************
+ * Open MCT Web, Copyright (c) 2014-2015, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT Web is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT Web includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+/*global define*/
+
+define(
+    function () {
+        "use strict";
+
+        /**
+         * Defines the `mct-image` directive.
+         *
+         * This takes one attribute, `src`, whose value is an Angular
+         * expression that resolves to an image.
+         *
+         * If `src` is falsy, no image will be displayed (immediately.)
+         *
+         */
+        function MCTImage() {
+            function link(scope, element, attrs) {
+                var div;
+
+                // Add a div
+                element.html('<div></div>');
+                div = element.children().eq(0);
+            }
+
+            return {
+                scope: { src: "=" },
+                link: link
+            };
+        }
+
+    }
+);