I'd prefer not to incur a dependency on purescript-filterable as it lives outside of -contrib, meaning it could potentially block updates to this.

@xgrommx Would you consider adjusting this to only include the improvements that don't rely on packages outside -contrib? In that case I can help push this along to get merged.

#25 applies these functions outside of the -filterable dependency, and without the additional functions from profunctor-lenses, but I'd be happy to merge anything adding the profunctor-lenses additions in the future!