- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

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

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

Use __FBSDID().
Also some minor copyright style cleanups.

Add support for the "nullconsole" console type, for systems with
neither a video console nor a serial port. Use it if the RB_MUTE
flag is set.

Submitted by: Doug Ambrisko <ambrisko@whistle.com>
Reviewed by: jhb