undo SocketDefaults class; plumb in new UdpSocket option attributes

src/node/wscript

@@ -23,7 +23,6 @@ def build(bld):
         'node-list.cc',
         'socket.cc',
         'socket-factory.cc',
-        'socket-defaults.cc',
         'packet-socket-factory.cc',
         'packet-socket.cc',
         'udp.cc',
@@ -57,7 +56,6 @@ def build(bld):
         'node-list.h',
         'socket.h',
         'socket-factory.h',
-        'socket-defaults.h',
         'packet-socket-factory.h',
         'udp.h',
         'tcp.h',