* Fix test_gpu_coordinate. * Use `gpu_coord_descent` in test. * Reduce number of running rounds. * Remove nthread. * Use githubusercontent for r-appveyor. * Use githubusercontent in travis r tests.
* Fix test_gpu_coordinate. * Use `gpu_coord_descent` in test. * Reduce number of running rounds. * Remove nthread. * Use githubusercontent for r-appveyor. * Use githubusercontent in travis r tests.