bsd15 on real hardware

  I did a pre-run on upgrading my 14.3/stable system to 15 today.  It was an
in-place from-source upgrade (main-n279819-6ea7e1f92882).

  I ran into the IPv[46] addresses on interfaces vs bridge issue (I use bhyve)
	I'd seen people talking about it in email but didn't appreciate how
	it might get me, but new where to start digging.  IPv4 was easy, IPv6
	took more digging (auto_linklocal).
  I transitioned from BIOS to UEFI, which was a little unexpected (not sure
	why I didn't start UEFI), so I had to fix resolution/font/etc.
	(efi_max_resolution="1280x1024", screen.font="8x16")
	Most of the time was spent trying to figure out what was "wrong" with
	vidcontrol (no modes); "sysctl machdep.bootmethod" got me on the
	right track.
  I have a trackpad-mouse on the console, and the mouse device changed.
	Looks like event-devices aren't supported by stock moused so I
	resorted to using the older drivers.  Seems like that would be
	something you'd want to have a good solution for, otherwise there
	will be a lot of questions and people will get stuck on old code.
	(hw.usb.usbhid.enable="0"; ums_load="YES")

  I had to blow away the old object tree (cleanuniverse) because it wasn't
totally happy.  But compiled kernel, rebooted, made a new poudriere jail
and compiled my whole local repo, then upgraded world, then force-upgraded
all packages.