- 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

- remove non-existent input directories from the configs
- add the target-arch to the project name where applicable (arch dependend code)
- fix comment for __FreeBSD__ [1]

Noticed by: bz [1]

Mechanically add a config for all missing drivers.

No cross-referencing was added to the configs, so no
automatic linking to the documentation of other subsystems.

Drivers which already contain doxygen markup:
agp ath bktr bxe cxgb cxgbe dpt drm e1000 iir
ixgbe mwl nxge ofw pccard siba wpi xen