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

Trivial cleanup, no functional change.

Interesting cases, most likely from CMU Mach sources.

Implement an optional delay to the ddb reset/reboot command.

This allows textdumps to be run automatically with unattended reboots
after a resonable timeout, while still permitting an administrator to
break into debugger if attached to the console at the time of the
event for further debugging.  Cap the maximum delay at 1 week to avoid
highly accidental results, and default to 15s in case of problems
parsing the timeout value.

Move hex2dec helper function from db_thread.c to db_command.c to make
it generally available and prefix it with a "db_" to avoid namespace
collisions.

Reviewed by:	rwatson
MFC after:	4 weeks

commands are available from 'boot -d'.

Suggested by:	dfr

define a set of named scripts.  Each script consists of a list of DDB
commands separated by ";"s that will be executed verbatim.  No higher
level language constructs, such as branching, are provided for:
scripts are executed by sequentially injecting commands into the DDB
input buffer.

Four new commands are present in DDB: "run" to run a specific script,
"script" to define or print a script, "scripts" to list currently
defined scripts, and "unscript" to delete a script, modeled on shell
alias commands.  Scripts may also be manipulated using sysctls in the
debug.ddb.scripting MIB space, although users will prefer to use the
soon-to-be-added ddb(8) tool for usability reasons.

Scripts with certain names are automatically executed on various DDB
events, such as entering the debugger via a panic, a witness error,
watchdog, breakpoint, sysctl, serial break, etc, allowing customized
handling.

MFC after:	3 months

ready for it yet.