Fix some stuff for later use

src/de/steamwar/command/SWCommand.java

@@ -44,6 +44,10 @@ public class SWCommand extends AbstractSWCommand<CommandSender> {
 
     private List<String> defaultHelpMessages = new ArrayList<>();
 
+    protected SWCommand(String command) {
+        this(command, null);
+    }
+
     protected SWCommand(String command, String permission) {
         super(CommandSender.class, command);
         this.permission = permission;