psd.tree().children() result wrongly equals psd.layers

[f2d]

With latest master version or 3.2.0 release, I try the following code in browser:

var PSD = require('psd');
PSD.fromDroppedFile(file).then(
    (psd) => {
        console.log(psd.tree().children());
        console.log(psd.layers);
    }
);

Both lines give the same - flat array of all layers in the PSD file.

With patched version from #150, psd.tree().children() gives the expected - array of layers only at the root of tree.