CoxPH: reduce memory usage + speed-up utilizing LocalMR task for Efron
CoxPH: reduce memory usage + speed-up utilizing LocalMR task for Efron

h2oai/h2o-dev,michalkurka/h2o-3,spennihana/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,h2oai/h2o-3,spennihana/h2o-3,michalkurka/h2o-3,h2oai/h2o-dev,spennihana/h2o-3,h2oai/h2o-dev,spennihana/h2o-3,h2oai/h2o-3,h2oai/h2o-dev,michalkurka/h2o-3,h2oai/h2o-dev,michalkurka/h2o-3,spennihana/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,spennihana/h2o-3,h2oai/h2o-3,h2oai/h2o-dev,h2oai/h2o-dev,h2oai/h2o-3,h2oai/h2o-3,spennihana/h2o-3