Rework `interval_score` function so that it also works with quantiles, not only ranges

[nikosbosse]

[nikosbosse]

The input format would then be something like function(predictions, quantiles, true_value).

Also think about whether the current function really needs several true_values as input

[nikosbosse]

A quantile_score function could look like this:

quantile_score <- function(true_values,
                           predictions,
                           quantiles,
                           weigh = TRUE,
                           separate_results = FALSE) {
  
  
  2 * (ifelse(y <= predictions) - quantiles) * (predictions - true_value)
  
  
}

reference: https://journals.plos.org/ploscompbiol/article/file?type=supplementary&id=info:doi/10.1371/journal.pcbi.1008618.s001

[nikosbosse]

This is superseded by the new wis() function