Add no_gateway option to UInt160's to_json().
Add no_gateway option to UInt160's to_json().

wilsonianb/ripple-lib,darkdarkdragon/ripple-lib,wilsonianb/ripple-lib,wilsonianb/ripple-lib,ripple/ripple-lib,ripple/ripple-lib,ripple/ripple-lib,darkdarkdragon/ripple-lib,darkdarkdragon/ripple-lib,ripple/ripple-lib