Summary of important user-visible changes for statistics 1.7.6

Important Notice:
mean, median, std, var, and mad shadow core Octave's functions before Octave 9.1
incompatibility with the nan package

News:

• There are 2 new functions (factoran and multiway) introduced in this release.
• Updated documentation and demos for distribution objects.
• cvpartition and crossval are now fully MATLAB compatible.
• Several bug fixes related to various issues #232, #226
• ClassificationKNN can use either 'exhaustive' or 'kdtree' search methods for prediction.