Record 2018-07-11 Version: V1.0 Detail: Three platforms supported. 2018-07-22 Version: V1.0 Detail: add "not_in_downloader" folder to support downloading douyin videos by douyin user id. 2018-08-05 Version: V1.1 Detail: Support downloading zhihu video. 2018-08-21 Version: V1.2.0 Detail: Support downloading douyu, ted, cntv video. 2018-08-26 Version: V1.2.1 Detail: Support downloading zhanqi video. 2018-09-03 Version: V1.2.1 Detail: Start to support live cache. 2018-09-21 Version: V1.3 Detail: Support downloading tecent video. 2019-07-12 Version: V2.0.0 Detail: Clean the code