[gta02-core] ECN0015 (Calypso headset interface) -> Done

[Werner Almesberger]

We've killed that one good by now - time to consider it done.

I merged the R4405/7 change from 33 R to 0 R and then nothing into
a straight removal and I also added a remark that ECN0030 ends the
Calypso era anyway.

- Werner