Attach (recommended) or Link to PDF file here:
http://mariovalle.name/SciViz/1-s2.0-S0097849310001846-main.pdf

Configuration:
- Web browser and its version: Using pdf.js from Node.js through npm package `pdfjs-dist`
- Operating system and its version: Windows 10 64bits
- PDF.js version: 2.6.347
- Is a browser extension: No

Steps to reproduce the problem:
1. Load the file in acrobat
2. In document properties look at the Author field: it is `Samuel Silva; Beatriz Sousa Santos; Joaquim Madeira`
3. Look at  Additional metadata > advanced > dc:creator. It is marked as `seq container` and contains the 3 authors.
4. Using the code below gives: `"Author": "Samuel Silva"` that is, only the first one. And `"dc:creator": "Samuel SilvaBeatriz Sousa SantosJoaquim Madeira"`, that is the three authors squashed together without separators.

What is the expected behavior? (add screenshot)
In both fields the three authors as a single string with some sort of separator between them. Note that other pdf files that contains multiple authors already have them as a single string with names separated by commas.

The code used:
```
var pdfjsLib = require("pdfjs-dist/es5/build/pdf.js");
var pdfPath = "http://mariovalle.name/SciViz/1-s2.0-S0097849310001846-main.pdf";
var loadingTask = pdfjsLib.getDocument(pdfPath);
loadingTask.promise
  .then(function (doc) {
    var lastPromise;
    lastPromise = doc.getMetadata().then(function (data) {
      console.log(JSON.stringify(data.info, null, 2));
      if (data.metadata) {
        console.log(JSON.stringify(data.metadata.getAll(), null, 2));
      }
    });
  });
```
constructor(data) {
    assert(typeof data === "string", "Metadata: input is not a string");
    
    data = this._repair(data);
    
    const parser = new SimpleXMLParser({ lowerCaseName: true });
    const xmlDocument = parser.parseFromString(data);
    this._metadataMap = new Map();
    if (xmlDocument) {
      this._parse(xmlDocument);
    }
    this._data = data;
  }
  _repair(data) {
    
    return data
      .replace(/^[^<]+/, "")
      .replace(/>\\376\\377([^<]+)/g, function (all, codes) {
        const bytes = codes
          .replace(/\\([0-3])([0-7])([0-7])/g, function (code, d1, d2, d3) {
            return String.fromCharCode(d1 * 64 + d2 * 8 + d3 * 1);
          })
          .replace(/&(amp|apos|gt|lt|quot);/g, function (str, name) {
            switch (name) {
              case "amp":
                return "&";