Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Use ASCII characters for box/line characters in frames.4th

Committed with changes to support the following from loader.conf(5):
+ console="vidconsole comconsole" (not just console="comconsole")
+ boot_serial="anything" (not just boot_serial="YES")
+ boot_multicons="anything" (unsupported in originally-submitted patch)

PR: conf/121064
Submitted by: koitsu
Reviewed by: gcooper, adrian (co-mentor)
Approved by: adrian (co-mentor)

PC98 uses the different frame code.

Add a new bootloader menu. Pull in screen.4th and frames.4th from the
examples directory to support it. This is installed only on i386 for
now. It will be enabled in a later commit.

Approved by: re