Added export and import for settings

options/export.js

@@ -0,0 +1,57 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+(function(){
+	"use strict";
+
+	const settings = require("./settings");
+	const logging = require("./logging");
+	const input = document.getElementById("settings");
+	settings.onloaded(function(){
+		var data = {};
+		settings.forEach(function(def){
+			data[def.name] = def.get();
+		});
+		input.value = JSON.stringify(data, null, "\t");
+
+		input.addEventListener("input", function(){
+			try {
+				var newSettings = JSON.parse(this.value);
+				var isValid = true;
+
+				
+				Object.entries(newSettings).forEach(function(entry){
+					const [name, value] = entry;
+					const def = settings.getDefinition(name);
+					if (!def){
+						logging.warning("Setting %s not known.");
+						isValid = false;
+					}
+					else if (def.get() !== value){
+						const invalid = def.invalid(value);
+						if (invalid){
+							isValid = false;
+							logging.warning("Invalid setting for %s:", name, value, invalid);
+						}
+					}
+				});
+				if (isValid){
+					this.classList.remove("invalid");
+					Object.entries(newSettings).forEach(function(entry){
+						const [name, value] = entry;
+						if (settings[name] !== value){
+							settings[name] = value;
+						}
+					});
+				}
+				else {
+					this.classList.add("invalid");
+				}
+			}
+			catch (e){
+				logging.warning("Invalid JSON:", e);
+				this.classList.add("invalid");
+			}
+		});
+	});
+}());