Translators

stronger baidu().
stronger caiyun().
stronger deepl(). 83
rebuild niutrans().
stronger parsing data about splitting paragraph.

upgrade packaging of project.
upload package to Anaconda. 90

fix func en_tran().
fix iflytek() about getting language_map.
add self.default_country by os.environ, merged from kevindragon 79
stronger papago().

fix func request_server_region_info().

upgrade readme.md

add lingvanex().
add mglip().
add niutrans().
change baidu()'s default `version` to `v1`, and fix regexp bug. 78

todo:
add niutrans() but need to debug it.
change baidu()'s default `version` to `v1`, need to debug `v2`.