Load defaults from example config

This makes some options non-optional -- allowing for a smaller config file.
This also removes the X-Sendfile example, bucause the proxy server should
handle static files directly and the option is not at all specific to this
particular application (and general Flask options aren't documented).

README.md

@@ -75,8 +75,8 @@ Setting up the server
 		# # OR:
 		# pip install uwsgi
 
-  4. Configure the server by changing options in config.py, which is a Flask
-	configuration file.
+  4. Configure the server by adding options to `config.py`.
+       See `config-example.py` for defaults.
 
   5. Start the server: