addonPostprocessTree(type, tree) {
    return addonProcessTree(this.project, 'postprocessTree', type, tree);
  }
Runs addon post-processing on a given tree and returns the processed tree.

    This enables addons to do process immediately **after** the preprocessor for a
    given type is run, but before concatenation occurs. If an addon wishes to
    apply a transform before the preprocessors run, they can instead implement the
    preprocessTree hook.

    To utilize this addons implement `postprocessTree` hook.

    An example, would be to apply some broccoli transform on all JS files, but
    only after the existing pre-processors have run.

    ```js
    module.exports = {
      name: 'my-cool-addon',
      postprocessTree(type, tree) {
        if (type === 'js') {
          return someBroccoliTransform(tree);
        }

        return tree;
      }
    }

    ```

    @private
    @method addonPostprocessTree
    @param  {String} type Type of tree
    @param  {Tree}   tree Tree to process
    @return {Tree}        Processed tree