WAF: make all ns3 modules register themselves in the environment; link the run-tests program with all ns3 modules, not with a hardcoded list.

src/node/wscript

@@ -1,5 +1,8 @@
 ## -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 
+def configure(conf):
+    conf.env.append_value('NS3_MODULES', 'ns3-node')
+
 
 def build(bld):
     node = bld.create_obj('cpp', 'shlib')