function tep_get_tax_description wrt no tax

Hi, while trying to resolve:

http://forums.oscommerce.com/topic/391988-duplicating-zonesphp-i-do-need-help-please/#entry1664734

I've found that in catalog/includes/functions/general.php that this:

function tep_get_tax_description

will not work, if no tax is selected on the admin side, that is for the constant "TEXT_NONE".

It seems to me that the "TEXT_NONE" have an ambigous meaning, sometimes it means "for all"... like for zones in a country, sometimes it means undefined/not set.

In that case will cause issues while calculating taxes.

Suggestion: Add a clarification for what "TEXT_NONE" means in each circumstance.

Sara