documentation of pg_select command.

Laser.

Please check compile errors before you commit!

member offset.

per bug report from Stefan Hadjistoytchev.  There are some cases
where the dot notation works, but there are more where it doesn't.
Eventually ought to consider fixing the parser to allow cases like
func().field, but for now this is the simplest patch.

laser

Thanks.

Teodor Sigaev