Translators

recover youdao()

raise fixed
add license in code

print --> raise,warn
add 'zh-cn'
del client=t

On PYPI, rst --> md.

fix "translators.google.cn"

translate_api` --> 'translators'
Implementing multiple translators is my pursuit, and the existing module name is ambiguous,
so upgrading the module name is something I have been exploring and thinking about.
Now the name `translators` is more in line with the meaning of the module itself,
and now I have no hesitation to upgrade, although the code upgrade and optimization is limited.

upgraded `Warning`.