[PyGreSQL] Reading values after INSERT

[Christoph Zwerschke]

Christoph Zwerschke schrieb:
> Ok, I'll try to work a bit on this along these lines tonight. Maybe I'll 
> also solve the open problem with composite primary keys.

Composite primary keys are now working. I have added a few unit tests 
for these as well and made the code a bit cleaner.

Will look into the "returning *" issue again later this weekend.

-- Christoph