Re: Review: B-Tree emulation for GIN

> I'm pretty certain I recall Greg Stark recommending that we adopt
> something like that as the standard numeric representation of zero.
> It didn't get done yet, but it might happen someday.

Changes:
- use NULL as left-most value. It's safe because NULL numeric value
   cannot be an argument for any function except gin_numeric_cmp and it
   cannot be returned in regular SQL query.
- fix uninstall script for support numeric type.
-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
                                                    WWW: http://www.sigaev.ru/