Restructured MeasurementDistribution to have child classes EmpiricalMeasurementDistribution and AnalyticMeasurementDistribution - this resulted in many classes being altered.
Added ChiSquare distribution methods to MathsUtils.
Added more covariance methods to MatrixUtils.
Changed method signatures for initialisers for multivariate channel calculator (transfer entropy and mutual information) classes to have source dimensions before destination dimensions, in line with the addObservations (etc.) methods.