Added setting of channel topics

lib/Client.js

@@ -1141,6 +1141,42 @@ var Client = (function () {
 			}
 			return this.getPMChannel("id", data.id);
 		}
+	}, {
+		key: "setTopic",
+		value: function setTopic(channel, topic) {
+			var callback = arguments.length <= 2 || arguments[2] === undefined ? function (err) {} : arguments[2];
+
+			var self = this;
+
+			return new Promise(function (resolve, reject) {
+
+				self.resolveDestination(channel).then(next)["catch"](error);
+
+				function error(e) {
+					callback(e);
+					reject(e);
+				}
+
+				function next(destination) {
+
+					var asChan = self.getChannel("id", destination);
+
+					request.patch(Endpoints.CHANNELS + "/" + destination).set("authorization", self.token).send({
+						name: asChan.name,
+						position: 0,
+						topic: topic
+					}).end(function (err, res) {
+						if (err) {
+							error(err);
+						} else {
+							asChan.topic = res.body.topic;
+							resolve();
+							callback();
+						}
+					});
+				}
+			});
+		}
 
 		//def addServer
 	}, {
@@ -1437,7 +1473,7 @@ var Client = (function () {
 					} else {
 						channId = destination;
 					}
-				if (channId) resolve(channId);
+				if (channId) resolve(channId);else reject();
 			});
 		}
 	}, {