Removed all references to using namespace std to help solve compilation problems

under Windows and IRIX.

Also integrated small change to lib3ds from Drew for IRIX compilation.

include/osgDB/FieldReader

@@ -14,7 +14,7 @@
 #include <iostream.h>
 #else
 #include <iostream>
-using namespace std;
+using std::istream;
 #endif
 
 namespace osgDB {

include/osgDB/Output

@@ -16,7 +16,7 @@
 #include <fstream.h>
 #else
 #include <fstream>
-using namespace std;
+using std::ofstream;
 #endif
 
 namespace osgDB {

include/osgGLUT/Viewer

@@ -22,13 +22,14 @@
 
 #include <string>
 
+/*
 #ifdef OSG_USE_IO_DOT_H
 #include <iostream.h>
 #else
 #include <iostream>
 using namespace std;
 #endif
-
+*/
 namespace osgGLUT{
 
 /** A basic viewer base class which provides a window, simple keyboard and mouse interaction.