* fix cran check
* change required R version because of utils::globalVariables
* temporary commit, monotone not working
* fix test
* fix doc
* fix doc
* fix cran note and warning
* improve checks
* fix urls
* [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