Add 'aeq.project.getLayersDeep' method?

[runegan]

Original report by Zack Lovatt (Bitbucket: zlovatt, GitHub: zlovatt).

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We have aeq.getItemsDeep to create a flat arrayEx of nested items in a folder. Having this for layers in a comp (and precomps) would be good.

Pass in a comp, get a flat arrayEx of all layers in the comp and precomps.

/**
 * Returns an arrayEx of all layers in comp and precomps

 * @param  {CompItem} comp   The comp to flatten.
 * @return {aeq.arrayEx}     ArrayEx with Layer objects.
 */
function getLayersDeep (comp, returnArrayEx) {
    // The returnArrayEx param is so we can skip the converting to arrayEx when
    // recursing. It is not meant to be used outside of this function.
    var layers = [];

    aeq.forEachLayer(comp, function (layer) {
        if (aeq.isPrecomp(layer))
            layers.push.apply(layers, getLayersDeep(layer.source, false));
        else
            layers.push(layer);
    });

    // Skip converting to arrayEx when function is called by it self.
    if (returnArrayEx === false)
        return layers;

    return aeq.arrayEx(layers);
}