Changelog: - add new RandomGroundTruth model which allows the user to create random ground truth by sampling real ground truth; - implemented inheritance throughout the package to make RandomGroundTruth and GroundTruth interoperable; - move sampling functions to own file in the utils submodule; - remove unnecessary steps found in the computations of granularity.py and rater_vitality.py - allow only name-wise GT selection in granularity.py and rater_vitality.py to allow interoperability with RandomGroundTruth; - fix the initialisation of BoundingBox with the correct type; - update the default Kappa for zero counts to 0.0; - smaller optimisations, such as deletion of useless imports.