Feature request: unitPreferences

[rotsee]

There is no method for extracting unit preferences (https://unicode.org/cldr/charts/46/supplemental/unit_preferences.html#road).

I'd suggest: extractUnitPreferences() (like e.g. extractTerritoryContainmentGroups() this data is independent of locale)

This is often used in tandem with https://unicode.org/cldr/charts/46/supplemental/unit_conversions.html, which would probably be good to have as well.

[papandreou]

PR very welcome ;)