Doc modernization (#3474)

* 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

doc/sphinx_util.py

@@ -7,24 +7,10 @@ import subprocess
 
 READTHEDOCS_BUILD = (os.environ.get('READTHEDOCS', None) is not None)
 
-if not os.path.exists('../recommonmark'):
-    subprocess.call('cd ..; rm -rf recommonmark;' +
-                    'git clone https://github.com/tqchen/recommonmark', shell = True)
-else:
-    subprocess.call('cd ../recommonmark/; git pull', shell=True)
-
 if not os.path.exists('web-data'):
-    subprocess.call('rm -rf web-data;' +
-                    'git clone https://github.com/dmlc/web-data', shell = True)
+  subprocess.call('rm -rf web-data;' +
+                  'git clone https://github.com/dmlc/web-data', shell = True)
 else:
-    subprocess.call('cd web-data; git pull', shell=True)
+  subprocess.call('cd web-data; git pull', shell=True)
 
-
-sys.path.insert(0, os.path.abspath('../recommonmark/'))
 sys.stderr.write('READTHEDOCS=%s\n' % (READTHEDOCS_BUILD))
-
-
-from recommonmark import parser, transform
-
-MarkdownParser = parser.CommonMarkParser
-AutoStructify = transform.AutoStructify