Add support for Metrowerks Codewarrior build under Windows.

src/osg/DisplaySettings.cpp

@@ -4,6 +4,8 @@
 
 using namespace osg;
 
+using namespace std;
+
 DisplaySettings::DisplaySettings(const DisplaySettings& vs):Referenced()
 {
     copy(vs);

src/osg/Image.cpp

@@ -11,6 +11,7 @@
 
 
 using namespace osg;
+using namespace std;
 
 Image::Image()
 {

src/osg/Notify.cpp

@@ -1,9 +1,7 @@
 #include <osg/Notify>
 #include <string>
 
-#if defined(__BCPLUSPLUS__)
-using std::toupper;
-#endif
+using namespace std;
 
 osg::NotifySeverity osg::g_NotifyLevel = osg::NOTICE;
 std::ofstream *osg::g_NotifyNulStream;