- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

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

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

style cleanup: Remove duplicate $FreeBSD$ tags.

These files had tags after teh copyright notice,
inside the comment block (incorrect, removed),
and outside the comment block (correct).

Approved by: rwatson (mentor)

Add an implementation of fabs() (which is quite trivial).
When it is called directly, gcc is smart enough to generate inline
code for it, which is why it wasn't noticed before that it was missing.

fabs() would probably better fit into libm, but it has traditionally been
in libc on FreeBSD, so there is probably software around that makes
assumptions about this by now.