- 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 r277487:
An update for the i915 GPU driver, which brings the code up to Linux
commit 4d93914ae3db4a897ead4b.

MFC r277959 (by adrian):
Fix backlight for ivybridge based laptops (and whatever else comes through
this codepath.)

MFC r278146:
Do not attach to the unsupported chipsets, unless magic tunable is
frobbed.

MFC r278147, r278148:
Fix sign for the error code returned from the driver-specific code.

MFC r278152:
Do not access gmbus_ports array past its end.

MFC r278159 (by emaste):
Remove duplicate intel_fbc_enabled prototype.

drm/i915: Add HW context support

This feature is required by Mesa 9.2+. Without this, a GL application
crashes with the following message:
# glxinfo
name of display: :0.0
Gen6+ requires Kernel 3.6 or later.
Assertion failed: (ctx->Version > 0), function handle_first_current,
file ../../src/mesa/main/context.c, line 1498.
Abort (core dumped)

Now, Mesa 10.2.4 and 10.3-rc3 works fine:
# glxinfo
name of display: :0
display: :0 screen: 0
direct rendering: Yes
...
OpenGL renderer string: Mesa DRI Intel(R) 965GM
OpenGL version string: 2.1 Mesa 10.2.4
...

The code was imported from Linux 3.8.13.

This an MFC of r271705.

Approved by: re (glebius)
Reviewed by: kib@
Tested by: kwm@, danfe@, Henry Hu,
Lundberg, Johannes <johannes@brilliantservice.co.jp>,
Johannes Dieterich <dieterich.joh@gmail.com>,
Lutz Bichler <lutz.bichler@gmail.com>,
Relnotes: yes

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

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

Add the code for new Intel GPU driver, which supports GEM, KMS and
works with new generations of GPUs (IronLake, SandyBridge and
supposedly IvyBridge).

The driver is not connected to the build yet.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week