Unit tests

- Test `directMessage(string, string)` (so singular) to send to myself
- Adding such a test will test the direct message receive handler which helps us a lot in increasing code coverage

source/birchwood/client.d

@@ -1217,6 +1217,11 @@ public class Client : Thread
 
         // }
 
+        /**
+         * Test sending a message to myself (singular)
+         */
+        client.directMessage("Message to myself", "birchwood");
+
         // TODO: Don't forget to re-enable this when done testing!
         Thread.sleep(dur!("seconds")(15));
         client.quit();