Add login with token method

lib/client.js

@@ -1746,6 +1746,18 @@ MatrixClient.prototype.loginWithCas = function(ticket, service, callback) {
     }, callback);
 };
 
+/**
+ * @param {string} token Login token previously received from homeserver
+ * @param {module:client.callback} callback Optional.
+ * @return {module:client.Promise} Resolves: TODO
+ * @return {module:http-api.MatrixError} Rejects: with an error response.
+ */
+MatrixClient.prototype.loginWithToken = function(token, callback) {
+    return this.login("m.login.token", {
+        token: token
+    }, callback);
+};
+
 // Push operations
 // ===============