Sql.pgsql NG unleashed in 8.1

Several things:
- Would someone review the fixes/changes I made to Stdio.Buffer?
- Anyone that uses PostgreSQL with Pike is encouraged to try
  the new pgsql driver.  Making a test-suite for it is difficult
  since it needs a proper database to test it with.  So, the next best
  thing is lots of beta-testers.
  It finally passed all alpha-testing internally here, so please
  give it a whirl.
- There currently is some kind of obscure corruption/race condition
  in the old pgsql driver; it is quite unclear under which circumstances
  it surfaces.  It might be in the _PGsql helper function.  If the
  current driver works, I will backport it to 8.0.  Backporting it to
  7.8 is not possible due to the dependency on Stdio.Buffer.
  The new driver does not have any C-helpers any longer, and preliminary
  benchmark tests have not revealed performance loss.
- This new driver will only work in a pike with threading support.
  Are there many environments that do not support that yet these days?
-- 
Stephen.