Tertius.SettingsManager = {
  defaultSettings: {
    fontSize: "100",
    ruby: "1",
    presentation: "parallel"
  },
  load: function(cb) {
    Tertius.DataStorage.loadJSON("settings", Tertius.SettingsManager, function() {
      if (!Tertius.SettingsManager.settings) Tertius.SettingsManager.settings = Tertius.SettingsManager.defaultSettings;
      cb();
    });
  },
  save: function() {
    Tertius.DataStorage.saveJSON("settings", Tertius.SettingsManager.settings);
  },
};
@@ -297,16 +297,36 @@
 ttings =
+ %7B%7D;%0A      for (k in
  Tertius
@@ -357,16 +357,147 @@
 Settings
+) %0A      if (!Tertius.SettingsManager.settings%5Bk%5D) Tertius.SettingsManager.settings%5Bk%5D = Tertius.SettingsManager.defaultSettings%5Bk%5D
 ;%0A      

Allow new settings which don't appear in the file.