Localization

Number and date formatting has been added for Danish (da), Dutch (nl), Swedish (sv), Italian (it), Belgian French (fr-BE), and Flemish (nl-BE). Thanks to Karel Goossens of BTR Services, Belgium, for supplying these.

The class hierarchy has been changed so that non-English numberers no longer inherit from Numberer_en, but from a new AbstractNumberer class; the functionality that is intended to be generic across languages (but overridable) has been separated from the functionality that is specific to English.