tell pybindgen not to disable inheritance on classes that end with Helper, and rescan

examples/tutorial/sixth.cc

@@ -20,8 +20,7 @@
 #include "ns3/simulator-module.h"
 #include "ns3/node-module.h"
 #include "ns3/helper-module.h"
-#include "ns3/ascii-trace-helper.h"
-#include "ns3/pcap-helper.h"
+#include "ns3/trace-helper.h"
 
 using namespace ns3;