Corrections to README (Mapbox API).
Corrections to README (Mapbox API).

alexreisner/geocoder,sjaveed/geocoder,donbobka/geocoder,AndyDangerous/geocoder,brian-ewell/geocoder,mdebo/geocoder,ankane/geocoder,aceunreal/geocoder,FanaHOVA/geocoder,Devetzis/geocoder,rdlugosz/geocoder,TrangPham/geocoder,tiramizoo/geocoder