Add ignore comments

[larsoner]

In most packages like pyflakes, pep8, and flake8 you can do something like a # noqa:

bad_style = whatever  # noqa

It seems like there should be something like this for pydocstyle. It would allow temporary workarounds (or maybe permanent enough ones!) for things like #68, #171, #189, and any other shortcomings that may be present.

I'm happy to try adding this. I'd probably try to follow what flake8 does since it seems pretty complete:

• # noqa no checks
• # pydocstyle: noqa no checks
• # noqa: D200 ignore a specific error or comma-separated list of errors

[larsoner]

Dup of #97