libpqxx update

My new C++ frontend to PostgreSQL, libpqxx, now has a little home page
of its own. Find it at:

http://members.ams.chello.nl/j.vermeulen31/proj-libpqxx.html

History is included on the page. Among the hottest updates are support
for back_insert_iterators in TableWriter (which lets you write tuples to
a table using "*i++ = Row;" syntax), and a more self-reliant setup of
the little test programs so the Makefile can run a simple regression
test with a minimum of human preparation.

Documentation is still in SGML, similar to the dialect found in the
PostgreSQL docs themselves. The tutorial has been expanded slightly,
and a "why yet another C++ SQL frontend" section has been added.

Let me know what you think!

Jeroen