Allow multiple locales

[1ec5]

Apparently the language parameter will accept multiple IETF language tags, separated by commas. We should replace the locale property on GeocodeOptions with a locales property of type [Locale].

/cc @apendleton @cammace

[1ec5]

According to the Geocoding API documentation, multiple language tags produces results with text_{language}, place_name_{language}, and language_{language} properties.

[cammace]

Tracking this on the android side of things here: mapbox/mapbox-java#511