Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Use dtrace -s instead of /bin/sh for DTrace scripts.

Remove copy/pasteo in the copyright notice.

Add a new script, hotopen, which shows what uid is opening files
on a per second basis. While here clean up the Makefile as well.

MFC after: 1 week