- 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 r275576: remove opensolaris cyclic code, replace with high-precision callouts

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

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

Implement DTrace for PowerPC. This includes both 32-bit and 64-bit.

There is one known issue: Some probes will display an error message along the
lines of: "Invalid address (0)"

I tested this with both a simple dtrace probe and dtruss on a few different
binaries on 32-bit. I only compiled 64-bit, did not run it, but I don't expect
problems without the modules loaded. Volunteers are welcome.

MFC after: 1 month

Add device part of DTrace/MIPS code

Custom DTrace kernel module files plus FreeBSD-specific DTrace providers.