- 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

Set magic fbsd:nokeywords property that allows files to bypass
keyword expansion. (file-specific replacement for CVSROOT/exclude)

Remove the last vestiges of the userconfig option. None of this actually
did anything, so this commit should be considered a NO-OP.

Document boot_cdrom, boot_multicons, and boot_serial.
Reduce diffs between help.common and loader(8).
Mention that boot_userconfig is currently a no-op.

Add help file for pc98.