LightGBM

[R-package] [ci] Fix CI timeouts for Mac builds on Travis (fixes #3091) (#3092)

* [R-package] use processx to speed up builds

* different fix

* echoing more frequently

* fix it

* more stdout

* use print() instead of message()

* shell tricks

* fix message

* travis

* Update .ci/test_r_package.sh

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>