Source obtained from http://sourceforge.net/projects/wmacpi/files/.
2003 July 16 0.90
Make the time display show '--:--' instead of '00:00' when the
time remaining is 0 - I think this is reasonable, since it'll only
get into this state when the present rate value is 0. This only
happens when the battery is fully charged and neither discharging
or charging, or when the battery is completely drained. In any of
these states the time remaining is of very little interest, so we
don't lose anything. We also get to handle the (sadly, very
common) case where the ACPI subsystem doesn't report sane values
for the things we depend on.
