loo v2.4.0

Bug fixes

• Fixed a bug in relative_eff.function() that caused an error on Windows when
  using multiple cores. (#152)

• Fixed a potential numerical issue in loo_moment_match() with split=TRUE. (#153)

• Fixed potential integer overflow with loo_moment_match(). (#155, @ecmerkle)

• Fixed relative_eff() when used with a posterior::draws_array. (#161, @rok-cesnovar)

New features

• New generic function elpd() (and methods for matrices and arrays) for
  computing expected log predictive density of new data or log predictive density
  of observed data. A new vignette demonstrates using this function when doing
  K-fold CV with rstan. (#159, @bnicenboim)