Fix import

* Add options page to import/export (export also possible from popup)
* Change popup import to open options
* Add separate store.js file for common code between popup and options
* Bump version to 1.5.0

options.js

@@ -0,0 +1,46 @@
+import { NotificationCenter, Store } from './store.js';
+
+const export_elt = document.querySelector('#export');
+const import_elt = document.querySelector('#import');
+const notification_elt = document.querySelector('#notification');
+const notification_text_elt = document.querySelector('#notification-text');
+
+let notification = new NotificationCenter(notification_elt, notification_text_elt);
+let store = new Store(notification);
+let background_port = browser.runtime.connect({name:"background"});
+
+async function init()
+{
+	export_elt.addEventListener('click', () => {
+		if(store.key === null)
+			notification.show_error('Cannot export before login');
+		else
+			store.export();
+	});
+	import_elt.addEventListener('click', () => {
+		if(store.key === null)
+			notification.show_error('Cannot import before login');
+		else
+			store.import();
+	});
+
+	document.querySelector('#notification img').addEventListener(
+		'click', notification.close_notification.bind(notification));
+
+	background_port.postMessage({command: 'init'});
+	background_port.onMessage.addListener((message) => {
+		if(message.type === 'state')
+		{
+			if(message.data.key !== null)
+				store.loadState(message.data);
+		}
+		else if(message.type === 'notification')
+			notification.show_notification(message.data);
+		else
+			notification.show_error(`unexpected background message with type ${message.type}`);
+	});
+}
+
+init().catch(error => {
+	notification.show_error(error);
+});