* Reorganize contributor's doc
* Address comments from @trivialfis
* Address @sriramch's comment: include ABI compatibility guarantee
* Address @rongou's comment
* Postpone ABI compatibility guarantee for now
* Added some instructions on using MinGW-built XGBoost with python.
* Changes according to the discussion and some additions
* Fixed wording and removed redundancy.
* Even more fixes
* Fixed links. Removed redundancy.
* Some fixes according to the discussion
* fixes
* Some fixes
* fixes
* 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