Simplify room filtering a bit

The lookup table seems a bit redundant

Author: pbock

lib/parse.js

@@ -11,15 +11,11 @@ module.exports = function parse(xml, rooms) {
 	const baseUrl = $('conference base_url').text();
 
 	const filterRooms = rooms && rooms.length;
-	const roomFilter = {};
-	for (let roomName of rooms || []) {
-		roomFilter[roomName] = true;
-	}
 
 	const days = $('day').map((i, day) => {
 		const $day = $(day);
 		const events = $day.find('room').filter((i, room) => {
-			return filterRooms ? $(room).attr('name') in roomFilter : true;
+			return filterRooms ? rooms.indexOf($(room).attr('name')) !== -1 : true;
 		}).find('event').map((i, event) => {
 			const $event = $(event);
 			const t = (selector) => $event.find(selector).text() || null;