- 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 r266728,266731,266735,266736,268135,268960,269833
Update apr 1.4.8 -> 1.5.1
Update apr-util 1.5.2 -> 1.5.3
Update serf 1.3.4 -> 1.3.7
Update svnlite 1.8.8 -> 1.8.10
Deal with svnlite.1 manpage.

MFC r262324: serf 1.3.4 - improve SSL handling with svn-1.8.8 and other
speedups and quality of life fixes.

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

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

Update serf 1.2.1 -> 1.3.0 for svn

Import serf-1.3.0