* To improve the situation for language bindings, pixbufs can now
be constructed from data in GBytes, and pixbuf data can also be
extracted in this form. The GBytes data is treated as readonly,
and gdk_pixbuf_get_pixels() will create a copy. To avoid this
copy, a new function gdk_pixbuf_read_pixels() was introduced
which returns a const pointer to the data without copying.
