fixed reading unicode strings

[NotOfficer]

Example:

const buffer = Buffer.from('TQBhAGwAZQB0AO0AbgAgAGQAZQAgAHMAaQBnAGkAbABvACAAbgBlAHYAYQBkAG8A', 'base64');
const strBefore = String(buffer);
const strAfter = buffer.toString('utf-16le');
console.log(strBefore); // > Malet�n de sigilo nevado
console.log(strAfter);  // > Maletín de sigilo nevado