Don't request the same capability more than once in a single request

Author: mbax

src/main/java/org/kitteh/irc/client/library/defaults/listener/DefaultCapListener.java

@@ -169,7 +169,7 @@ private void fireAndCapReq(@NonNull CapabilityNegotiationResponseEventWithReques
         List<String> requests = responseEvent.getRequests();
         if (!requests.isEmpty()) {
             CapabilityRequestCommand capabilityRequestCommand = new CapabilityRequestCommand(this.getClient());
-            requests.forEach(capabilityRequestCommand::enable);
+            requests.stream().distinct().forEach(capabilityRequestCommand::enable);
             capabilityRequestCommand.execute();
         }
     }