Error messages from PL/Python now always mention the function name in the
CONTEXT: field. This also obsoletes the few places that tried to do the
same manually.
Regression test files are updated to work with Python 2.4-2.6. I don't have
access to older versions right now.
for its arguments. Also add a regression test, since someone apparently
changed every single plpython test case to use only named parameters; else
we'd have noticed this sooner.
Euler Taveira de Oliveira, per a report from Alvaro
(I didn't use his patch, however). A void-returning PL/Python function
must return None (from Python), which is translated into a void datum
(and *not* NULL) for Postgres. I also added some regression tests for
this functionality.
