v0.2-5

New Features

• PlackettLuce() now supports MAP estimation with a multivariate normal prior on log-worths and/or a gamma prior on ranker adherence.
• PlackettLuce() now returns log-likelihood and degrees of freedom for the null model (where all outcomes, including ties, have equal probability).
• There is now a vcov method for Plackett-Luce trees.

Changes in Behaviour

• itempar.PlackettLuce() now always returns a matrix, even for a single node tree.

Bug Fixes

• pltree() or PlackettLuce() with grouped rankings now work correctly with weights.