* Adding Java/Scala doc build to Jenkins CI
* Deploy built doc to S3 bucket
* Build doc only for branches
* Build doc first, to get doc faster for branch updates
* Have ReadTheDocs download doc tarball from S3
* Update JVM doc links
* Put doc build commands in a script
* Specify Spark 2.3+ requirement for XGBoost4J-Spark
* Build GPU wheel without NCCL, to reduce binary size
* Change doc build to reST exclusively
* Rewrite Intro doc in reST; create toctree
* Update parameter and contribute
* Convert tutorials to reST
* Convert Python tutorials to reST
* Convert CLI and Julia docs to reST
* Enable markdown for R vignettes
* Done migrating to reST
* Add guzzle_sphinx_theme to requirements
* Add breathe to requirements
* Fix search bar
* Add link to user forum
* Fix doc build
ReadTheDocs build has been broken for a while due to incompatibilities between
commonmark, recommonmark, and sphinx. See:
* "Recommonmark not working with Sphinx 1.6"
https://github.com/rtfd/recommonmark/issues/73
* "CommonMark 0.6.0 breaks compatibility"
https://github.com/rtfd/recommonmark/issues/24
For now, we fix the versions to get the build working again
* Fix search bar
