[avr] add milli to delta reply
[spid+fluksod] accept fixed-point counter values from delta
[fluksod] filter on int counters
[fluksod] publish counter values on mqtt as string iso float
[tmpod] round deltas to 1/1000th
[fluksod] add sensor floor switch
[avr] send delta on each pulse
[avr] initialize millis to 0
[tmpod] fix rounding error
[fbackup] make sure we can restore a uint32