Add client functions around new synapse CAS login

lib/client.js

@@ -1728,6 +1728,31 @@ MatrixClient.prototype.loginWithSAML2 = function(relayState, callback) {
     }, callback);
 };
 
+/**
+ * @param {module:client.callback} callback Optional.
+ * @return {module:client.Promise} Resolves: TODO
+ * @return {module:http-api.MatrixError} Rejects: with an error response.
+ */
+MatrixClient.prototype.getCasServer = function(callback) {
+    return this._http.authedRequest(
+        callback, "GET", "/login/cas", undefined, undefined
+    );
+};
+
+/**
+ * @param {string} ticket (Received from CAS)
+ * @param {string} service Service to which the token was granted
+ * @param {module:client.callback} callback Optional.
+ * @return {module:client.Promise} Resolves: TODO
+ * @return {module:http-api.MatrixError} Rejects: with an error response.
+ */
+MatrixClient.prototype.loginWithCas = function(ticket, service, callback) {
+    return this.login("m.login.cas", {
+        ticket: ticket,
+        service: service
+    }, callback);
+};
+
 // Push operations
 // ===============