v0.2-1

New features

• Add pkgdown site.
• Add content to README (fixes #5).
• Add plot.PlackettLuce method so that plotting works for a saved "PlackettLuce" object

Improvements

• Improved vignette, particularly example based on beans data (which has been updated).
• Improved help files particularly ?PlackettLuce and new package?PlackettLuce. (Fixes #14 and #21).

Changes in behaviour

• maxit defaults to 500 in PlackettLuce.
• Steffensen acceleration only applied in iterations where it will increase the log-likelihood (still only attempted once iterations have reached a solution that is "close enough" as specified by steffensen argument).

Bug fixes

• coef.pltree() now respects log = TRUE argument (fixes #19).
• Fix bug causes lack of convergence with iterative scaling plus pseudo-rankings.
• [.grouped_rankings] now works for replicated indices.