add ToLTSVString method

convert object to LTSV string.

e.g.

// convert to LTSV string
var source = new { hoge = "fuga", bar = "baz" };
Console.WriteLine(source.ToLTSVString()); // hoge:fuga\tbar:baz
pack v1.1.0
modify README by v1.1.0

add sample "Convert to LTSV string".