Toml spec support

[wade-cheng]

This library doesn't seem to support parsing literal strings ('). https://toml.io/en/v1.0.0#string

With nanoserde = "0.2.1", see

fn main() {
    let toml = r"winpath  = 'C:\Users\nodejs\templates'";
    nanoserde::TomlParser::parse(toml).unwrap();
}