Add notes on accuracy and data types to README (issue #477)
Add notes on accuracy and data types to README (issue #477)

https://github.com/alexreisner/geocoder/issues/477
andreamazz/geocoder,tortuba/geocoder,malandrina/geocoder,epyatopal/geocoder,GermanDZ/geocoder,rayzeller/geocoder,sjaveed/geocoder,TrangPham/geocoder,FanaHOVA/geocoder,jaigouk/geocoder-olleh,jaigouk/geocoder-olleh,ankane/geocoder,rios1993/geocoder,mdebo/geocoder,sideci-sample/sideci-sample-geocoder,donbobka/geocoder,eugenehp/ruby-geocoder,Devetzis/geocoder,StudioMelipone/geocoder,mveer99/geocoder,guavapass/geocoder,mehlah/geocoder,crdunwel/geocoder,AndyDangerous/geocoder,alexreisner/geocoder,sr-education/geocoder,ivanzotov/geocoder,gogovan/geocoder-olleh,3mundi/geocoder,gogovan/geocoder-olleh,aceunreal/geocoder,davydovanton/geocoder,jgrciv/geocoder,brian-ewell/geocoder,moofish32/geocoder,boone/geocoder,tiramizoo/geocoder,rdlugosz/geocoder