The format::csv module handles the reading and writing of comma-separated text,
or newline-delimited records of text with generic field delimiters.

    let w = csv::newwriter(os::stdout, '|');

    csv::write(&w, ["field1", "field2", "field3"])!;
    // "field1|field2|field3\n"

When reading, fields wrapped in double-quotes will be unwrapped, and
backslash-escaped double-quotes will be unescaped.

When writing, double-quotes will be backslash-escaped, and fields containing an
occurence of the delimiter will be wrapped in double-quotes.
