Renaming cups to cups-base and depend on cups-filters

[Pierre Pronchery <khorben%defora.org@localhost>]

			Dear tech-pkg@,

I just figured that print/cups does not work as expected without
print/cups-filters also being installed. Printing then fails with:

> Returning IPP client-error-document-format-not-supported for Send-Document
in the logs, or with lp(1) complaining that

> Unsupported document-format "application/pdf
Apparently this is the case since version 1.6.0, as some core
functionality has been moved to cups-filter by then.

This made me lose more time than I feel comfortable admitting here. In
order to avoid this for anyone (including myself) in the future, I would
suggest to:
- rename print/cups to print/cups-base
- let print/cups-filters depend on print/cups-base instead
- add a package print/cups depending on print/cups-base and
  print/cups-filters

Any comments/objections?

If I end up being tasked with this, I will need help to recursively
update links to "../../print/cups-base/buildlink3.mk" and bump revisions
as appropriate. As an intermediate step I could add a link in
"../../print/cups/buildlink3.mk" depending on
"../../print/cups-base/buildlink3.mk", build I would rather DTRT right away.

Cheers,
-- 
khorben