Move getFriendlyRoomName to Room. Add recalculate() function to cache info.

lib/utils.js

@@ -42,7 +42,7 @@ module.exports.encodeUri = function(pathTemplate, variables) {
  * Applies a map function to the given array.
  * @param {Array} array The array to apply the function to.
  * @param {Function} fn The function that will be invoked for each element in
- * the array.
+ * the array with the signature <code>fn(element){...}</code>
  * @return {Array} A new array with the results of the function.
  */
 module.exports.map = function(array, fn) {
@@ -108,6 +108,15 @@ module.exports.isFunction = function(value) {
     return Object.prototype.toString.call(value) == "[object Function]";
 };
 
+/**
+ * Checks if the given thing is an array.
+ * @param {*} value The thing to check.
+ * @return {boolean} True if it is an array.
+ */
+module.exports.isArray = function(value) {
+    return Boolean(value && value.constructor === Array);
+};
+
 /**
  * Checks that the given object has the specified keys.
  * @param {Object} obj The object to check.