Added isPrivate to channels

src/PMChannel.js

@@ -20,6 +20,10 @@ class PMChannel {
 		}
 		return null;
 	}
+	
+    get isPrivate(){
+        return true;
+    }
 }
 
 module.exports = PMChannel;

src/channel.js

@@ -36,6 +36,10 @@ class Channel {
     toString(){
         return "#" + this.name;
     }
+    
+    get isPrivate(){
+        return false;
+    }
 }
 
 module.exports = Channel;