- 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

Port of ppbus standalone framework to the newbus system.

Note1: the correct interrupt level is invoked correctly for each driver.
For this purpose, drivers request the bus before being able to
call BUS_SETUP_INTR and BUS_TEARDOWN_INTR call is forced by the ppbus
core when drivers release it. Thus, when BUS_SETUP_INTR is called
at ppbus driver level, ppbus checks that the caller owns the
bus and stores the interrupt handler cookie (in order to unregister
it later).

Printing is impossible while plip link is up is still TRUE.
vpo (ZIP driver) and lpt are make in such a way that
using the ZIP and printing concurrently is permitted is also TRUE.

Note2: specific chipset detection is not done by default. PPC_PROBE_CHIPSET
is now needed to force chipset detection. If set, the flags 0x40
still avoid detection at boot.

Port of the pcf(4) driver to the newbus system (was previously directly
connected to the rootbus and attached by a bogus pcf_isa_probe function).