[Add] Cache models on instantiation

...to remove need for Edit to persist these immediately, which in
turn causes #770 and #678

platform/core/src/models/ModelCacheService.js

@@ -0,0 +1,55 @@
+/*****************************************************************************
+ * 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';
+
+    function ModelCacheService() {
+        this.cache = {};
+        this.cached = {};
+    }
+
+    ModelCacheService.prototype.put = function (id, model) {
+        this.cached[id] = true;
+        this.cache[id] = model;
+    };
+
+    ModelCacheService.prototype.get = function (id) {
+        return this.cache[id];
+    };
+
+    ModelCacheService.prototype.has = function (id) {
+        return this.cached[id];
+    };
+
+    ModelCacheService.prototype.remove = function (id) {
+        delete this.cached[id];
+        delete this.cache[id];
+    };
+
+    ModelCacheService.prototype.all = function () {
+        return this.cache;
+    };
+
+    return ModelCacheService;
+});