blazer: Fix shutdown delay

'offdelay' as used by this driver is meant to be in the .2-.9 (12..54 seconds) and 01-10 (60..600 seconds) range.
blazer: Fix shutdown.return

'SnR0000' is meant to put the UPS down and not return
'Sn' should be used instead when ondelay is 0
blazer: Fix test.battery.start

T00 doesn't make any sense: the range should be 01-99 minutes
blazer: Fix minor error in battery guesstimation

We need both battery.voltage.low and battery.voltage.high to 'guesstimate' the battery charge
blazer: Fix shutdown sequence

Split stop pending shutdown and shutdown itself so that if we have problems stopping the shutdown (e.g. there's no shutdown pending and the UPS, because of that, echoes back the
command) we can still shutdown the UPS.
blazer: Fix user manual

Fix minor errors
Add ranges
Fix test.battery.start (i.e. minutes instead of seconds)
blazer: Fix {usb,ser} manual

Split the old blazer manual in two manuals named after their executables with a common source.
blazer: Add more log infos in instcmd
blazer: Versioning
blazer: Fix user manuals

{Serial,USB}-specific sections belong to 'Extra arguments' section
blazer: Fix blazer_{ser,usb} + TESTING

Those things are useless when TESTING is defined
blazer: Cosmetic changes
blazer: Fix a discrepancy in the handling of instant commands

Check if the reply we got back from the UPS is 'ACK' also for the commands stored in the array.
blazer: Support UPSes that reply '(ACK' when an instant command succeeds