Fix table formatting in zh translation.
Merge pull request #1721 from blackpuppy/zh

[zh] fix sphinx build errors from last pull request #1712
Merge pull request #1722 from blackpuppy/zh

[zh] fix sphinx build errors from last pull request #1721
[zh] try to fix sphinx build warnings in build #1987
Exclude zh from PDF builds.

We don't have the correct latex packages on the server to build a PDF
version of the zh docs.
Merge branch 'master' into zh
[zh] correct meta data: change lang=en to lang=zh
[en] correct errors in original text
[zh] correct language: change en to zh in URLs