- Group C API. - Add C API sphinx doc. - Consistent use of `OptionalArg` and the parameter name `config`. - Remove call to deprecated functions in demo. - Fix some formatting errors. - Add links to c examples in the document (only visible with doxygen pages) - Fix arrow.
The documentation of xgboost is generated with recommonmark and sphinx. You can build it locally by typing "make html" in this folder. Checkout https://recommonmark.readthedocs.org for guide on how to write markdown with extensions used in this doc, such as math formulas and table of content.