Gdk::Window::create_gl_context(): Remove refreturn
Gdk::Window::create_gl_context(): Remove refreturn

gdk_window_create_gl_context() gives the caller a reference. Then refreturn
in _WRAP_METHOD() will most probably cause a memory leak.

GNOME/gtkmm,GNOME/gtkmm,GNOME/gtkmm,GNOME/gtkmm