libpqxx milestone

As of now, all public methods and overridables (in other words, the
entire API) in libpqxx are covered by the built-in regression test.

libpqxx is an alternative C++ frontend for PostgreSQL--a replacement
for libpq++--that I hope will become the standard C++ language
binding for this DBMS.

Full method coverage in the self-test was the most significant
milestone to be achieved before libpqxx is to be submitted for
prospective inclusion in the PostgreSQL source tree. The remaining
milestone is porting the Little Brother network monitoring tool from
libpq++ to libpqxx. I do not expect this to present much effort.

As usual, get the latest source tree from my homepage:
http://members.ams.chello.nl/j.vermeulen31/proj-libpqxx.html

Please let me know what you think!

Jeroen