faster printing of floats by divmod10() and others

new patch ... (code increase)

    case ENG:
    case SCI:
        n += write('E');
        if (exponent >= 0) n += write('+');
        else 
        {
            exponent = -exponent;
            n += write('-');
        }
        if (exponent < 10) n += write('0');
        n += print(exponent);
        break;