Refactor FileDownloader class to prepare to push functionality into subclasses (separated out curl exec from writing of file).
Begin incorporating callback to FileDownloader class.
Replace sample files with new content from RMN because of the new page structure.
Incorporate callback to FileDownloader subclass to prepare to push functionality into subclasses (separated out curl exec from writing of file).
Refactor FileDownloader class to comment out all methods better handled with a callback sent from client class.
Next step remove the comments, then possibly merge the WithCallback subclass up to the parent.