yardstick 0.0.7

• The global option, yardstick.event_first, has been deprecated in favor of
  the new explicit argument, event_level. All metric functions that previously
  supported changing the "event" level have gained this new argument.
  The global option was a historical design decision that can be classified as
  a case of a hidden argument.
  Existing code that relied on this global option will continue to work in this
  version of yardstick, however you will now get a once-per-session warning
  that requests that you update to instead use the explicit event_level
  argument. The global option will be completely removed in a future version.
  To update, follow the guide below (#163).

  `options(yardstick.event_first = TRUE)`  -> `event_level = "first"` (the default)
  `options(yardstick.event_first = FALSE)` -> `event_level = "second"`
  

• The roc_auc() Hand-Till multiclass estimator will now ignore levels in
  truth that occur zero times in the actual data. With other methods of
  multiclass averaging, this usually returns an NA, however, ignoring
  levels in this manner is more consistent with implementations in the
  HandTill2001 and pROC packages (#123).

• roc_auc() and roc_curve() now set direction = "<" when computing the
  ROC curve using pROC::roc(). Results were being computed incorrectly with
  direction = "auto" when most probability values were predicting the wrong
  class (#123).

• mn_log_loss() now respects the (deprecated) global option
  yardstick.event_first. However, you should instead change the relevant
  event level through the event_level argument.

• metric_set() now strips the package name when auto-labeling functions
  (@rorynolan, #151).

• There are three new helper functions for more easily creating custom
  metric functions: new_class_metric(), new_prob_metric(), and
  new_numeric_metric().

• Rcpp has been removed as a direct dependency.