Change default submission target from cperciva-panicmail@daemonology.net to
cperciva@freebsd.org.  Include the To: "name" in the variable, not just the
email address.

Avoid missed periods.

Use > instead of >> when first writing to a file we're constructing in parts.

Add quoting of strings containing variable expansions.

Exit if pkesh fails.

Set umask correctly: Panic emails might contain information we don't want
local unprivileged users to read.

If present, use the info.last symlink to locate the most recent panic.  If
not, fall back to using bounds as before.

Compare timestamps on vmcore.N and panicmail.N; otherwise we will miss sending
email for panics after numbers rotate back to zero.

Submitted by:	dt71 via freebsd-hackers
Style fixes.

Submitted by:	dt71
Add more quoting paranoia.  Not likely anyone will be running with a TMPDIR
which has spaces in it, but still...

Submitted by:	dt71
Change default address again, this time to use a + address for
improved ease of filtering.

Suggested by:	eadler
Change
	local tmpfile=`mktemp` || exit 1
into
	local tmpfile
	tmpfile=`mktemp` || exit 1
since the former is parsed as "local || exit 1" and loses the exit code
from mktemp.

Submitted by:	jilles
Add a public key which can be used to send me encrypted panics.
Add copyright and BSD license text.