We're now handling these values on the frontend, so can keep this simple.
fixes up:
Add numericality validation for *
Add translation for Active Record error message
The browser is now responsible for dealing with the decimal separator, for all numeric preferences (as input[type=number]; see Spree::Admin::BaseHelper::preference_field_tag). Calculators are the only place that numeric preferences are used.
It will enforce that only one comma or dot (depending on user's locale) is entered, thus avoiding any ambiguity, and mis-interpretation (eg 100,001 could be interpreted as more than 100 thousand or 100 with a decimal place).
