Prepare the 2.4.0 release (#1471)

Author: erikcs

r-package/grf/DESCRIPTION

@@ -1,6 +1,6 @@
 Package: grf
 Title: Generalized Random Forests
-Version: 2.3.2
+Version: 2.4.0
 Authors@R: c(
     person("Julie", "Tibshirani", role = "aut", email = "jtibs@cs.stanford.edu"),
     person("Susan", "Athey", role = "aut"),

r-package/grf/NAMESPACE

@@ -23,19 +23,15 @@ S3method(print,grf)
 S3method(print,grf_tree)
 S3method(print,rank_average_treatment_effect)
 S3method(print,tuning_output)
-export(average_late)
-export(average_partial_effect)
 export(average_treatment_effect)
 export(best_linear_projection)
 export(boosted_regression_forest)
 export(causal_forest)
 export(causal_survival_forest)
-export(custom_forest)
 export(generate_causal_data)
 export(generate_causal_survival_data)
 export(get_forest_weights)
 export(get_leaf_node)
-export(get_sample_weights)
 export(get_scores)
 export(get_tree)
 export(grf_options)
@@ -53,9 +49,6 @@ export(regression_forest)
 export(split_frequencies)
 export(survival_forest)
 export(test_calibration)
-export(tune_causal_forest)
-export(tune_instrumental_forest)
-export(tune_regression_forest)
 export(variable_importance)
 importFrom(Matrix,Matrix)
 importFrom(Rcpp,evalCpp)