Bug 3516 [REVISED] Display picture of patrons in OPAC

Bug 3516 [REVISED] Display picture of patrons in OPAC

This patch adapts the patron image display script from the
self-checkout module to optionally display the image of the
logged-in user on their personal information page (opac-userupdate.pl).
The script changes the method choosing which image to display
from using a passed cardnumber to using the borrowernumber of
the logged-in user.

A system preference is added, OPACpatronimages, to control
whether these images are displayed.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Verified that patron image shows only when system preference is turned on
and that there are no display problems for patrons without patron image.