dir.files does not traverse symlinked directories

[miloss]

If you have symlinks to other directories, they are not being followed but returned as files. For example, assume the following structure added to current test code, where testdir inside testdir4 is symlink:

test 
└─ fixtures
   └─ testdir4
      └─ testdir --> ../testdir

Then the following test case will fail:

it("should iterate files of symlinked directories (recursively)", function(done) {
    dir.files(tdir4, function(err, files) {
        should.not.exist(err);
        var relFiles = files.map(function(curPath) {
            return path.relative(fixturesDir, curPath);
        });
        relFiles.sort().should.eql([
            'testdir4/testdir/file1.txt',
            'testdir4/testdir/file2.text',
            'testdir4/testdir/subdir/file3.txt',
            'testdir4/testdir/subdir/file4.text'
        ]); // Will equal to ['testdir4/testdir']
        done();
    });
});

This was working previously and has degraded from v0.1.14 to v0.1.15.