[Seaside] Update for www.seaside.st PDF & persistence pages

[Stephan Eggermont]

Hello,

Some time ago I asked everyone having experience with
pdf generation and  persistence solutions to provide a
small piece of text/code on their experiences. The results
can be seen on:

http://www.seaside.st/documentation/persistence
http://www.seaside.st/documentation/pdfs

Sufficient time has passed to update the pages, so I
would like to ask all contributors (and new ones)
to take a critical look at what they provided and let
me know if a change is in order, preferably in the
form of a new paragraph to replace the old one.

Thanks for taking the time to make the Seaside
experience even better,

   Stephan Eggermont