GitLab

* add cuda quantile regression objective

* remove white space

* resolve merge conflicts

* remove useless changes

* remove useless changes

* enable cuda quantile regression objective

* add a test case for quantile regression objective

* remove useless changes

* remove useless changes

* reduce DP_SHARED_HIST_SIZE to 5176 for CUDA 10

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Co-authored-by: James Lamb <jaylamb20@gmail.com>