All-Angle Bundle Router about kfactory

[sebastian-goeldi]

Added by #305

[joamatab]

yes, that's correct

[tvt173]

to be picky, it would be great if the API doesn't change from the existing all-angle bundle router in gdsfactory. there's quite a bit of functionality packed into it, such as custom connectors, bends, cross-sections, etc.

[sebastian-goeldi]

I think I will not get around to not at the very least drop some args/kwargs. There are no cross-sections, But I could offer KCellEnclosure which would be cross-section on steroids as it can do it for multiple center pieces. But for starters, I would like to avoid that.

Also, there's a decision to make wrt how it looks like. I think for the low-level interface such as kfactory it doesn't make much sense to do stuff like resolution of factories by name. I mean we can, but then we would be forcing people's hands to create a pdk.

Also, there isn't really such a thing as passing references in kfactory. I could hack it for the virtual cells, but then the function footprints for virtual / all-angle would deviate significantly from manhattan routing.