* 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
Current version of xgboost.readthedocs.io has a broken search box.
Enabling themes on ReadTheDocs is known to break the search function, as
reported in
[this document](https://github.com/rtfd/readthedocs.org/issues/1487). To get
around the bug, we replace the `searchtools.js` file with our custom version.
