* gtk/gtkwidget.c (gtk_widget_set_double_buffered): Add a
function to set the DOUBLE_BUFFERED flag.
* gtk/gtkwidget.h: Add GTK_DOUBLE_BUFFERED flag to indicate whether
or not exposes done on the widget should be double-buffered.
* gtk/gtkenums.h (GtkTextDirection): Reverse order of enumerations
to be what would be expected. (Fixes problem with a
g_return_if_fail() validating a TextDirection enumeration)