Added classes for TemperatureScaling and IsotonicCalibration for multi-class classification problems. Also added helper functions for calculating ECE and plotting calibration curves for the multi-class case.
Added classes for TemperatureScaling and IsotonicCalibration for multi-class classification problems. Also added helper functions for calculating ECE and plotting calibration curves for the multi-class case.

stellargraph/stellargraph,stellargraph/stellargraph