PUBDEV-4118: Adding helpful links
PUBDEV-4118: Adding helpful links

Added links to more information for using H2O with R.

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