o Updated Metrowerks files for MacOS. They aren't 100% there yet,

but getting there.

  o First cut of osgcluster demo.  Very simple beginings.  Alas
    I only one PC here so I can't test it in its current guise.

  o New support for NodeCallbacks, via AppCallback attached to
    osg::Node's, and a default osgUtil::AppVisitor which calls them on
    each frame.

  o Support for traversal masks in osg::NodeVisitor, osg::Node
    which allows nodes to be switched on or off via a bit mask.

  o Suppport for traversal number (frame number) and reference time
    into osg::NodeVisitor to handle syncronization of app and cull
    traversals.  This also assist clustering as traversal number
    master to slaves.

src/Demos/osgcluster/receiver.cpp

@@ -0,0 +1,104 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <sys/time.h>
+
+
+#include "receiver.h"
+
+Receiver::Receiver( void )
+{
+    _port = 0;
+    _initialized = false;
+    _buffer = 0L;
+}
+
+Receiver::~Receiver( void )
+{
+    close( _so );
+}
+
+bool Receiver::init( void )
+{
+    if( _port == 0 )
+    {
+	fprintf( stderr, "Receiver::init() - port not defined\n" );
+	return false;
+    }
+
+    if( (_so = socket( AF_INET, SOCK_DGRAM, 0 )) < 0 )
+    {
+        perror( "socket" );
+	return false;
+    }
+    int on = 1;
+    setsockopt( _so, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+
+    struct sockaddr_in saddr;
+    saddr.sin_family = AF_INET;
+    saddr.sin_port   = htons( _port );
+    saddr.sin_addr.s_addr =  0;
+
+    if( bind( _so, (struct sockaddr *)&saddr, sizeof( saddr )) < 0 )
+    {
+        perror( "bind" );
+	return false;
+    }
+
+    _initialized = true;
+    return _initialized;
+}
+
+
+void Receiver::setPort( const short port )
+{
+    _port = port;
+}
+
+void Receiver::setBuffer( void *buffer, const unsigned int size )
+{
+    _buffer = buffer;
+    _buffer_size = size;
+}
+
+void Receiver::sync( void )
+{
+    _initialized || init();
+
+    if( _buffer == 0L )
+    {
+	fprintf( stderr, "Receiver::sync() - No buffer\n" );
+	return;
+    }
+
+#ifdef __linux
+    socklen_t 
+#else
+    int
+#endif
+        size = sizeof( struct sockaddr_in );
+
+    fd_set fdset;
+    FD_ZERO( &fdset );
+    FD_SET( _so, &fdset );
+
+    struct timeval tv;
+    tv.tv_sec = 0;
+    tv.tv_usec = 0;
+
+    recvfrom( _so, (caddr_t)_buffer, _buffer_size, 0, 0, &size );
+    while( select( _so+1, &fdset, 0L, 0L, &tv ) )
+    {
+        if( FD_ISSET( _so, &fdset ) )
+	{
+            recvfrom( _so, (caddr_t)_buffer, _buffer_size, 0, 0, &size );
+	}
+    }
+}
+