[XeTeX] bidi & xwatermark are broken

[Arthur Reutenauer]

  Thanks.  The difference seems to be in the bidi version.  I have been
using version 13.5 dated 2013/05/28, from TeX Live 2013 pretest, while
you (Wilfred) are using version 12.2 dated 2013/04/04 -- presumably from
the frozen TeX Live 2012.  I can actually reproduce the behaviour you're
observing with bidi version 12.3 dated 2013/04/08.

	Arthur