Ability to exclude folders when opening a directory recursively

[Amatewasu]

It would be nice to add the ability to exclude some folders when opening a directory recursively.

We could, for example, exclude the .git directory of a folder, etc.

I think a list of strings with the folder names to exclude could be a good start for this feature.

[Amatewasu]

I've opened a PR to pass a callback to say whether we want to skip this directory or not. This can filter the names for example.

80

[tomayac]

This was closed via #80.