Merged fixes to the osg::GLExtensions function pointer code from Stefan Huber,

and a fix to osg::State's secondary color code from Bob Kuehne.

Moved the body of the getGLExtensionFuncPtr() into the header to help out
support for Windows mapping of different OpenGL extensions function ptr per
dll.

src/osg/Geometry.cpp

@@ -241,7 +241,6 @@ void Geometry::drawImmediateMode(State& state)
         }
     }
     
-    
     static SecondaryColor3ubvProc s_glSecondaryColor3ubv =
             (SecondaryColor3ubvProc) osg::getGLExtensionFuncPtr("glSecondaryColor3ubv","glSecondaryColor3ubvEXT");
     static SecondaryColor3fvProc s_glSecondaryColor3fv =