feature/metafeeds: Support for canteen meta feeds and index feed (#2)

* feature/metafeeds: Restructured API, splitted menu and meta feed

* feature/metafeeds: add field 'key' to Canteen

* feature/metafeeds: added helper function for reverse urls

* feature/metafeeds: added menu feed url to meta feed

* feature/metafeeds: added missing test

(added: testing meta feed rendering in retrievaltest)

* feature/metafeeds: added feed index page

* whitespace fix

* feature/metafeeds: added alias urls

* feature/metafeeds: moved meta feed default url

* feature/metafeeds: moved index generation to views

* feature/metafeeds: inlined builder instance creation

* feature/metafeeds: removed unused 'menu' parameter

* feature/metafeeds: replaced 'reverse' module with Flask's url_for

* feature/metafeeds: removed unused import

* feature/metafeeds: removed unused function parameters

* feature/metafeeds: moved menu feed url generation to views.py

* feature/metafeeds: cleanup debug prints

removing debug prints that should never have been committed.

stw_potsdam/config.py

@@ -17,7 +17,8 @@ def _get_config(filename):
 
 def _parse_canteen(config, canteen_name):
     get = partial(config.get, canteen_name)
-    return Canteen(name=get('name'),
+    return Canteen(key=canteen_name,
+                   name=get('name'),
                    street=get('street'),
                    city=get('city'),
                    id=get('id'),