AP_InertialSensor: add parameters for push-to-log interval and count
AP_InertialSensor: rename BAT_RAW to BAT_OPT
This becomes a bitmask of options for the BatchSampler
AP_InertialSensor: rename 'fast sample' to 'sensorrate sample'
AP_InertialSensor: const sensor-rate filter method
AP_InertialSampler: remove hard-coding of sample rate multiplier
AP_InertialSensor: use parameter to enable/disable sensor-rate logging
AP_InertialSensor: use a parameter to control sensor-rate logging
AP_InertialSensor: allow backends to override sensor data multiplier
e.g. some accelerometers are sensitive over wider ranges than the default 16G
AP_Inertialsensor: correct sample rate multiplier