Exeption when using strip:0

decompress-zip:0.0.6: Extracting a simple zip file with one level of empty directory at the root will throw an TypeError on path.join decompress-zip.js:259 if strip:1 is set

```
DecompressZip.prototype.extractFile = function (file, options) {
var destination = path.join(options.path, file.path);
```

The issue is in decompress-zip.js:109..120, which, instead of adding .path to the file entry, is returning the path directly in files.map().

```
files = files.map(function (file) {
                if (file.type !== 'Directory') {
...
                    return file.path //<-- this is replacing file with file.path in the map.
                    // should be:
                    //   file.path = path.join(dir.join(path.sep), filename);
                    //   return file

                }
```