Return metadata indicating that this is parallel_read_safe (python#14)

Author: Jon Wayne Parrott

python_docs_theme/__init__.py

@@ -5,3 +5,8 @@ def setup(app):
     current_dir = os.path.abspath(os.path.dirname(__file__))
     app.add_html_theme(
         'python_docs_theme', current_dir)
+
+    return {
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }