Adding an 'included' feature (along the existing 'omitted' feature)

Hi there,

Wondering whether you'd be open to support an 'included' selection, on top of 'omitted'.

I have a first version which is not really that great but works for me which is the important part here.

A better version would be to have a default selection of "Omitted" (default) or "Included".

Then a set of selection of each node type of: "Default", "Omitted", or "Included".

That way you would not have conflicts as my current version implies (i.e. you can make the same type at the same time included and omitted, which is probably bad, but that's just for me, so it's fine here.)

Thank you.
Alexis Wilke