Pathlib

[bagel897]

Use pathlib internally in Rope's resource, file and folder classes. This will allow more compatibility with other projects and increase speed. Resource should also implement os.PathLike.

Steps to implement:

1. add a pathlib property to resources
2. Make internal functions depend on pathlib versions

[lieryan]

I think having Resource, File, and Folder implement os.PathLike is a good idea.

However, the rest of proposal to use pathlib internally in Rope's resource is going to cause a lot of possibly backwards incompatible changes if not done carefully.

While in principle, I like the idea of using more pathlib, it needs to be done in a way that avoids breaking existing integrations.

[lieryan]

Related tickets: https://github.com/python-rope/rope/issues/562