sysreset command and sysclear command changes:

sysclear: disallow any arguments. sysreset: new optional "clear" and "normal" arguments: "normal" same as "sysreset", "clear" same as "sysclear" command.
Add help support for internal debugging commands:

$zapcmd, $locate (was locate) and $test commands: cmdlvl must also be at least prog + dev + debug, else commands are hidden/inaccessible.