Add-on, calibrated units: normalized_index and pct_to_action so readings compare across stations. When the line has no c

Add-on, calibrated units: normalized_index and pct_to_action so readings compare across stations. When the line has no calibration basis you get 422 with no_charge:true and reason:no-calibrated-for-this-line, and are NOT billed. Every record carries an offline-recomputable record_hash.