- 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

Hoist all the mergeinfo up to the root in preparation for enforcing merges
to the root only. All MFC's were rerecorded to the root.

Going forward, if an MFC includes mergeinfo, it will need to be made to
the root and committed from the root. Merges with --ignore-ancestry
or diff | patch can go anywhere.

The mergeinfo in HEAD is in a bad state from years of neglect and manual
tampering and this was branched into 10.x. This confuses the coalescing
code and prevents it from doing its job.

Approved by: re (gjb, implicit)

MFC r256450:

Rename libbsdyml to libyaml, make private, and bump
SHLIB_MAJOR to 1.0

Approved by: bapt
Approved by: re (glebius)

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

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

Add a stub manpage modeled over the libexpat one to explain to users not to use
this library outside of base.

Requested by: simon

Import libyaml as libbsdyml (private brand name)

LibYAML is a YAML 1.1 parser and emitter under MIT license which will
soon be used by the pkg boostrap (usr.bin/pkg) and bhyve

Reviewed by: roberto, antoine