- 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)

MFC r275866:

Parallelize building gnu/usr.bin/groff

This speeds up building the directory from the bootstrap-tools stage in
buildworld as well as building from the subdirectory

Based on a patch submitted via -arch:
https://lists.freebsd.org/pipermail/freebsd-arch/2014-December/016493.html

Submitted by: Jia-Shiun Li <jiashiun@gmail.com>
Sponsored by: EMC / Isilon Storage Division

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

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

Upgrade to Groff 1.17.