Optional Exporting or copying result with (,) as decimal mark

Hi,

in pgsql it's not possible to define, that numeric values are returned in
localized numeric format. In our case (Austria) we use comma as decimal mark
and not period.
When opening a pgadmin-exported CSV-File, we have troubles in Excel, because
it doesn't recognize numeric values properly. We would have to change the
locale settings in excel so that this works properly.

This patch enables an option in the query tool tab, where you can decide if
you like to use comma as decimal mark. It only applies on numeric values.
It also works, if you copy and paste from the result grid into excel.

I've done this work to make my people's life at work easier. If it's not
suitable for a release, please ignore it. In this case I'm going to build
"our own" version of pgadmin on each release.

Regards,
Jasmin