implementation and test for issue #21 beta prime distribution
Adding regularization support in iterative reweighted least squares for logistic regression.
Little parameter renaming for better consistency.
Adding a new tutorial sample applications to store code shown in the Wiki.
Merge pull request #50 from glyphard/gh_-21_betaprime_distribution

GH-21: Initial implementation for BetaPrime distribution by Ashley Messer.
Working on documentation; updating release notes.
Merge remote-tracking branch 'upstream/development' into development