DerivedMeasurements in devlib was changed to return DerivedMetrics
instead of Measurements. The former do not have "channel" attribute, so
just pass its name to WA's metrics.
Delvib now is capable of performing postprocessing of MeasurementCSV
files, instead of calculating additional metrics in WA this will be
performed externally. Currently support has been added for calculating
average power and cumulative energy.