Update py-Pillow to 2.3.1.

Changelog (Pillow)
==================

2.3.1 (2014-03-14)
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- Fix insecure use of tempfile.mktemp (CVE-2014-1932 CVE-2014-1933)
  [wiredfool]
Updated graphics/py-Pillow to 2.3.1
+ Pillow-2.4.0
py-Pillow is better.
Add missing py-xdg dependency. Bump PKGREVISION.
Updated misc/py-carddav to 0.7.0nb1