Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add various new keymaps:

addition: danish syscons keymap with accents

There are two danish keymap files shipping with FreeBSD:
danish.iso.kbd and danish.cp865.kbd. None of these support
accents by use of dead keys, which isn't crucial to Danes but
often used. This is a new keymap, danish.iso.acc.kbd, that's
based on danish.iso.kbd with the accent part taken from
german.iso.acc.kbd.

pl_PL.dvorak keymap for syscons.

Polish dvorak keymap by Robert Sebastian Gerus (17:05 01-07-2006
CEST) <arachnist@gmail.com>. Based on pl_PL.ISO-8859-2 and
us.dvorak keymaps.

British English Dvorak keymap for syscons.

Attached is a Dvorak keymap for British English, with a
pound-sterling symbol on on Shift-3 and some other characters
in different places to the US Dvorak keymap. I've based the
layout on the X.org GB keymap, Dvorak variant.

PR: conf/72978, kern/99692, conf/117257
Submitted by: Kim Norgaard <jasen@jasen.dk>, Robert Sebastian Gerus <arachnist@gmail.com>, "Benjamin A'Lee" <bma@subvert.org.uk>
MFC after: 1 week