find files that are not templates and not
    in the exclude_list for copying from template to image

def find_copies(input_dir, exclude_list):
    """
    find files that are not templates and not
    in the exclude_list for copying from template to image
    """
    copies = []

    def copy_finder(copies, dirname):
        for obj in os.listdir(dirname):
            pathname = os.path.join(dirname, obj)
            if os.path.isdir(pathname):
                continue
            if obj in exclude_list:
                continue
            if obj.endswith('.mustache'):
                continue

            copies.append(os.path.join(dirname, obj))

    dir_visitor(
        input_dir,
        functools.partial(copy_finder, copies)
    )
    return copies