- 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 r279965: Polish AHCI disk identify data and fix speed negotiation.

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

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

Import Zhixiang Yu's GSoC'13 AHCI emulation:
https://wiki.freebsd.org/SummerOfCode2013/bhyveAHCI

This provides ICH8 SATA disk and ATAPI ports, selectable
via the bhyve slot command-line parameter:

SATA
-s <slot>,ahci-hd,<image-file>

ATAPI
-s <slot>,ahci-cd,<image-file>

Slight modifications by: grehan@
Approved by: re@ (blanket)
Obtained from: FreeBSD GSoC'13