* add SHAP summary plot using ggplot2
* Update xgb.plot.shap
* Update example in xgb.plot.shap documentation
* update logic, add tests
* whitespace fixes
* whitespace fixes for test_helpers
* namespace for sd function
* explicitly declare variables that are automatically evaluated by data.table
* Fix R lint
Co-authored-by: Philip Hyunsu Cho <chohyu01@cs.washington.edu>
* [R] do not remove zero coefficients from gblinear dump
* [R] switch from stringr to stringi
* fix#1399
* [R] separate ggplot backend, add base r graphics, cleanup, more plots, tests
* add missing include in amalgamation - fixes building R package in linux
* add forgotten file
* [R] fix DESCRIPTION
* [R] fix travis check issue and some cleanup