remove --[no]filter option

I don't expect you to pull this as-is for two reasons. 1) It's blocking on a feature I [added to File::Next](https://github.com/petdance/file-next/pull/22) which you may want to rework. 2) I couldn't figure out how to add tests for it.

This would close #499 and #500. If my File::Next pull-request is applied and this PR updated to that version of File::Next, it would also close #501.