- 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 r281593,r282071,r282074,r282133,r282134,r282135,r282136,r282137,r282138:

r282071:

Integrate tools/regression/mqueue into the FreeBSD test suite as
tests/sys/mqueue

r282074:

Integrate tools/regression/aio/aiotest and tools/regression/aio/kqueue into the
FreeBSD test suite as tests/sys/aio

r282133:

Fill in the copyright boilerplate for the test program

r282134:

Add initial (unpolished) macros for interfacing with the FreeBSD test suite

This is very rough, but will be replaced/redesigned some time soon after I fix
the Jenkins breakage I introduced

r282135:

Use ATF_REQUIRE_KERNEL_MODULE instead of aio_available function

r282136:

- Use ATF_REQUIRE_KERNEL_MDOULE to require aio(4)
- Don't use /tmp as a basis for temporary files as it's outside of the ATF
sandbox
- Don't override MAX macro in sys/param.h

r282137:

Use PLAIN_REQUIRE_KERNEL_MODULE to require "mqueuefs"

r282138:

Adjust CFLAGS to find freebsd_test_suite/macros.h

Integrate tools/regression/mqueue into the FreeBSD test suite as
tests/sys/mqueue

MFC after: 1 week

Integrate tools/regression/mqueue into the FreeBSD test suite as tests/sys/mqueue

Integrate more tests into the FreeBSD test suite from tools/regression, etc

Add missing headers. While there, arrange headers alphabetically.

MFC after: 3 days

Fix compiling.

Add code to test POSIX message queue.