- 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

MFC r258355,258360,258400-258401,258406-258407,258418,258430,258439,258589-
258590,258592,258727-258728,258785, with the following descriptions:

Revisions 258400-258401,258406-258407,258590,258727-258728,258785:
+ Add a new `includes' module (see: bsdconfig includes -h) for exploring
the bsdconfig(8) API

Remaining revisions:
258592: Sort all the messages.subr files
258355: Fix typo in a comment in networking/device.subr
258360: Whitespace, style, and other changes in networking/device.subr
258418: Quote interface names for good measure in networking/device.subr
258430: Remove an unused line in networking/device.subr
258439: Minor bugfix to f_die() function in common.subr
258589: Minor bugfix to syscons_ttys module

Add new `includes' module for exploring the bsdconfig(8) API.