- 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

Import the common Flattened Device Tree infrastructure.

o fdtbus(4) - the main abstract bus driver for all FDT-compliant systems. This
is a direct replacement for the many incompatible bus drivers grouping
integrated peripherals on embedded platforms (like obio(4), ocpbus(4) etc.)

o simplebus(4) - bus driver representing ePAPR style 'simple-bus' node, which
is an umbrella device for most of the integrated peripherals on a typical
system-on-chip device.

o Other components (common routines library, PCI node processing helper
functions)

Reviewed by: imp
Sponsored by: The FreeBSD Foundation