Enable support for hosting on readthedocs

docs/source/conf.py

@@ -14,7 +14,13 @@
 
 import sys
 import os
-import sphinx_rtd_theme
+on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
+if on_rtd:
+    html_theme = 'default'
+else:
+    import sphinx_rtd_theme
+    html_theme = "sphinx_rtd_theme"
+    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
@@ -105,7 +111,6 @@
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #html_theme = 'default'
-html_theme = "sphinx_rtd_theme"
 
 # 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
@@ -114,7 +119,6 @@
 
 # Add any paths that contain custom themes here, relative to this directory.
 #html_theme_path = []
-html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".