- 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

Use 'manual page' instead of 'man page' for consistency.

Approved by: re (hrs)

Spelling fixes.

Assorted mdoc(7) fixes.

Create a man page for bus_child_present(9), a function to see if a
given device is considered accessible by its parent device bus driver
(or its parent, etc).