- 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 r269097:

Use the right length.

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

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

Add regression tests scripts for multi-IP FIBs exercising the send,
receive and forward path tagging packets with both the ifconfig fib
option or using ipfw, running ICMP6, TCP/v6 and UDP/v6 tests and
testing both setfib(2) as well as the SO_SETFIB socket option.

At 16 FIBs a total of over 64k return codes/replies/stati are checked,
sometimes multiple times (in different ways, e.g. the reflected request
as well as ipfw counter values).

The scripts need two or three machines to run and are thus not added
to the tools/regression framework but only to tools/test.

Sponsored by: Cisco Systems, Inc.