Move parser tests from rtd-build repo

[stsewd]

I'm not sure if I'm doing this in the proper way, hopefully it's a start.

[agjohnson]

👍 Yeah, so far so good. Is it easier to move this code over in parts like this, or to do all of readthedocs_build.config at once? If all at once, I'd say we can make doc_builder.config rely on the imported code with this PR as well.

[agjohnson]

So far looking good. We can either merge this PR now or attach more parts of readthedocs_build.config to this PR before merge. I'll leave this up to @stsewd which approach to take.

[stsewd]

Is it easier to move this code over in parts like this, or to do all of readthedocs_build.config at once?

I think is fine like this. But I'll attach another little part here (find.py)

[stsewd]

I move this file, and the encoding problem was gone. I think the issue was the file having a bad encoding when created. See readthedocs/readthedocs-build#45 and #3732 (comment)

[stsewd]

This is done, I'm leaving conf.py and validation.py for other PR. After travis is done and a re-review we can merge this :)

[stsewd]

I forgot about the unicode literals 😞 in the previous commit. Fixed

[agjohnson]

LGTM!