Add filename suffix until file not exists
    @return: filename

def getNonexistingFile(name):
    """Add filename suffix until file not exists
    @return: filename
    """
    num = 1
    stem, ext = os.path.splitext(name)
    filename = name
    while os.path.exists(filename):
        suffix = "-%d" % num
        filename = stem + suffix + ext
        num += 1
    return filename