[R] maintenance Nov 2017; SHAP plots (#2888)

* [R] fix predict contributions for data with no colnames

* [R] add a render parameter for xgb.plot.multi.trees; fixes #2628

* [R] update Rd's

* [R] remove unnecessary dep-package from R cmake install

* silence type warnings; readability

* [R] silence complaint about incomplete line at the end

* [R] initial version of xgb.plot.shap()

* [R] more work on xgb.plot.shap

* [R] enforce black font in xgb.plot.tree; fixes #2640

* [R] if feature names are available, check in predict that they are the same; fixes #2857

* [R] cran check and lint fixes

* remove tabs

* [R] add references; a test for plot.shap

R-package/R/xgboost.R

@@ -100,9 +100,12 @@ NULL
 #' @importFrom stats median
 #' @importFrom utils head
 #' @importFrom graphics barplot
+#' @importFrom graphics lines
+#' @importFrom graphics points
 #' @importFrom graphics grid
 #' @importFrom graphics par
 #' @importFrom graphics title
+#' @importFrom grDevices rgb
 #' 
 #' @import methods
 #' @useDynLib xgboost, .registration = TRUE