Unicode support

Hi Anoop and anyone else who might be interested,

I've been thinking about how the Unicode support might be improved to
allow the old 07.xx non-unicode style behaviour to work for those that
need it. At them moment, when we connect using on of the wide connect
functions, the CC->unicode flag is set to true. This only affects a few
options, such as pgtype_to_concise_type()'s mapping of PG types to SQL
types.

It seems to me that perhaps we should set CC->unicode = 1, only upon
connection to a Unicode database. Anything else, we leave it set to 0 so
that it always maps varchars etc to ANSI types, and handles other
encodings in single byte or non-unicode multibyte mode (which worked
fine in 07.xx where those encodings where appropriate, such as SJIS in
Japan). This should also help BDE based apps, which further research has
shown me are broken with Unicode columns in SQL Server and Oracle as
well as PostgreSQL (search unicode + BDE on Google Groups for more).

Am I seeing a possible improvement where in fact there isn't one, or
missing some obvious downside?

Regards, Dave.