transition to pathlib

[NileGraddis]

pathlib offers a nifty object-oriented API and lots of convenience functionality for interacting with fs paths. See the pep for more info.

We can probably replace some or all of our path-munging code with pathlib. It is, however python 3 only.

[NileGraddis]

I've switched brain_observatory/ecephys to pathlib on branch 673 as an experiment. Thoughts thus far:

• pathlib offers a larger set of convenience functions than os, which can be pretty nice for some operations (components jumps to mind)
• the object-oriented interface is not particularly helpful for this use case - most of the time I end up constructing a Path, immediately getting some information from it, and then throwing it away.

[njmei]

Hmm... yeah it looks like for your use case it might not make as much sense. For me, the strengths of pathlib are:

• More explicit _, ext = os.path.splitext(path) vs. ext = PurePath(path).suffix

• I like that Path objects auto normalize so you get Win + POSIX compatibility without having to be careful about mixed slashes

• I think best case os calls may make pathlib seem superfluous, but pathlib significantly improves the worst case os calls (no more os.path.dirname(os.path.dirname(os.path.abspath(__file__))) shenanigans)

But yeah, was only a suggestion, I think we can adopt and use on a case-by-case basis. It should be another tool in our toolbox.