Handle any reports of state changes for INDICATORs

branches: 1.4.30; 1.4.32;
Fix a typo in previous.

Use consistenly more meaningful messages in all envsys scripts.

branches: 1.2.4;
This one is shared for Indicators and Integers... update the comment.

Add the /etc/powerd/scripts/sensor_indicator to handle events on
indicator sensors.

Update powerd(8).

sync with HEAD

Pull up following revision(s) (requested by pgoyette in ticket #545):
etc/powerd/scripts/sensor_indicator: revision 1.5
sys/dev/sysmon/sysmon_envsys_tables.c: revision 1.11
sys/sys/envsys.h: revision 1.32
sys/dev/sysmon/sysmon_envsysvar.h: revision 1.43
sys/dev/sysmon/sysmon_envsys_events.c: revision 1.104
Provide names for the values associated with INDICATOR sensors.
1. Enable use of FMONSTCHANGED events for INDICATOR sensors
2. Update handling of FMONCRITICAL event reporting. The state
transition does not require a corresponding change in value.
With these changes, you can now have an INDICATOR sensor that
reports the presence or absence of a device, and (if the device
is present) separately monitor it for proper functioning.
Should address the concerns expressed recently with the commit
of changes to wmi(4) BBU handling.
Handle any reports of state changes for INDICATORs

sync with head