Added inlucde<osgSim/LightPointNode> to trPageArchive to get round IRIX build

problem.

src/osgPlugins/txp/TrPageArchive.h

@@ -31,14 +31,12 @@
 
 #include "TrPageParser.h"
 
+#include <osgSim/LightPointNode>
+
 #include <string>
 #include <vector>
 #include <memory> // for auto_ptr
 
-namespace osgSim{
-    class LightPointNode;
-}
-
 namespace txp
 {
     // this one handles different placement of light direction in osg and terrapage