Add in python3 documentation theme files and convert to using those.

doc/source/conf.py

@@ -38,7 +38,7 @@ extensions = [
 ]
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ['_templates', 'tools/templates']
 
 # The suffix of source filenames.
 source_suffix = '.rst'
@@ -105,7 +105,10 @@ pygments_style = 'sphinx'
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'default'
+# html_theme = 'default'
+html_theme = 'pydoctheme'
+html_theme_path = ['tools']
+html_theme_options = {'collapsiblesidebar': True}
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the