- Deleted unsupported SingleFilePhoneNumberMetadataProto.
Code changes:
 - Refactored metadata loading and closed all streams after loading.
 - Made isNumberGeographical public, and changed the geocoder to
   use this when checking whether to give a detailed answer or country-level
   only.
Build changes:
 - Use protobuf-javanano 3.0.0-alpha-7 from Maven Central.