ClockFace_menu: addSettingsFile with included Storage code

modules/ClockFace.md

@@ -199,4 +199,17 @@ require("ClockFace_menu").addItems(menu, save, {
 });
 E.showMenu(menu);
 
+```
+
+Or even simpler, if you just want to use a basic settings file:
+```js
+let menu = {
+  "": {"title": /*LANG*/"<clock name> Settings"},
+  /*LANG*/"< Back": back,  
+};
+require("ClockFace_menu").addSettingsFile(menu, "<appid>.settings.json", [ 
+  "showDate", "loadWidgets"
+]);
+E.showMenu(menu);
+
 ```

modules/ClockFace_menu.js

@@ -23,4 +23,26 @@ exports.addItems = function(menu, callback, items) {
         };
     }
   });
+};
+
+/**
+ * Create a basic settings menu for app, reading/writing to settings file
+ *
+ * @param {object} menu Menu to add settings to
+ * @param {string} settingsFile File to read/write settings to/from
+ * @param {string[]} items List of settings to add
+ */
+exports.addSettingsFile = function(menu, settingsFile, items) {
+  let s = require("Storage").readJSON(settingsFile, true) || {};
+
+  function save(key, value) {
+    s[key] = value;
+    require("Storage").writeJSON(settingsFile, s);
+  }
+
+  let toAdd = {};
+  items.forEach(function(key) {
+    toAdd[key] = s[key];
+  });
+  exports.addItems(menu, save, toAdd);
 };