- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

A number of places in the source tree still reference cuad.* after
sio(4) was deprecated by uart(4).

s/cuad/cuau/g/

PR: docs/171533
Reviewed by: imp
Approved by: cperciva (implicit)
MFC after: 3 weeks

Catch up with PHK's sio(4) cuaa->cuad rework [sys/dev/sio/sio.c rev. 1.456].

Add a small program to test/measure with the RFC 2783 API for timing
external signals.