Update README.rst

Author: matt-jordan

README.rst

@@ -1,10 +1,12 @@
 About
 -----
 
-This package contains a Python client library for the [Switchvox Extend API](http://developers.digium.com/switchvox/).
+This package contains a Python client library for the Switchvox Extend API.
 
 This library is only a very thin wrapper around the Extend API Methods, and seeks primarily to provide a Pythonic way of invoking the API.
 
+For more information on the Extend API, see the developer documentation: http://developers.digium.com/switchvox/
+
 Installation
 -----