add location user module

src/user/location.ts

+/**
+ *   Wechaty Chatbot SDK - https://github.com/wechaty/wechaty
+ *
+ *   @copyright 2016 Huan LI (李卓桓) <https://github.com/huan>, and
+ *                   Wechaty Contributors <https://github.com/wechaty>.
+ *
+ *   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.
+ *
+ */
+
+/**
+ * Location information
+ */
+class Location {
+
+  /**
+   * @param {number} latitude
+   * @param {number} longitude
+   * @param {?string} description
+   */
+  constructor (
+    public latitude    : number,
+    public longitude   : number,
+    public description : string,
+  ) {}
+
+}
+
+export { Location }