`weighted_cor`

to calculate weighted correlation between actual and observed values.`prop_within`

to calculate weighted proportion of predictions within a tolerance around actual values.

- Reduced minimal R version from 3.5 to 3.1.

- Clarified that R-squared is calculated with respect to the null model calculated from the actual values.

Elementary scoring functions for expectiles and quantiles.

`multi_metric`

: A way to create a named list of performance measures parametrized by a parameter.

Added the following convenience wrappers to `r_squared`

.

`r_squared_poisson`

`r_squared_gamma`

`r_squared_bernoulli`

Added function `weighted_var`

to calculate variance weighted by sampling weights.

Improvement of documentation and examples.

Better handling of Tweedie special cases.

More strict error handling.

Added median absolute error (and weighted_median, weighted_quantile)

Initial release.