Method set

tests/catch.h:4073–4077

        struct BoundUnaryMethod : IArgFunction<C>{
            BoundUnaryMethod( void (C::*_member)( M ) ) : member( _member ) {}
            virtual void set( C& p, std::string const& stringValue ) const {
                typename RemoveConstRef<M>::type value;
                convertInto( stringValue, value );
                (p.*member)( value );
            }
            virtual void setFlag( C& p ) const {
                typename RemoveConstRef<M>::type value;
                convertInto( true, value );