[rfc] remove names.scan()

[phi-gamma]

As far as I can grep, names.scan() alias scan_external_dir() is used nowhere and undocumented. There’s no test for it either. I’ve read some old posts on mailing lists and tex-sx that would suggest was intended to be called from fontspec. However, fontspec seems to do fine without it, so I guess we might as well drop the function.

[khaledhosny]

Well, it was meant to allow people to call fonts by name when using fontspec’s ExternalLocation, but it never got implemented. Not a reason to drop it IMO, but it can be moved to the new aux library and be a documented feature.

[phi-gamma]

okay, I’ll keep it, then.