Removes any pre-existing tracks that were not just downloaded

def remove_files():
    """
    Removes any pre-existing tracks that were not just downloaded
    """
    logger.info("Removing local track files that were not downloaded...")
    files = [f for f in os.listdir('.') if os.path.isfile(f)]
    for f in files:
        if f not in fileToKeep:
            os.remove(f)