fix(hac): get_similarity_matrix fails in case models is None
style: PEP8 for Claude's sc2llr.py
refactor(calibration): trivial ClusteringCalibration (wip...)
feat: linear regression for likelihood ratio estimation
feat: calibration of similarity matrix
chore(stats): move log-likelihood ratio estimators in pyannote.stats
feat: working implementation of ClusteringCalibration
feat: ClusteringCalibration (merge)