implement URL generation

move code for URL generation to model/urlbuilder.py
add format selection to input form
create output template

ddportfolioservice/lib/base.py

@@ -26,6 +26,7 @@ class BaseController(WSGIController):
                 add_fallback(lang)
             except:
                 pass
+        c.messages = { 'errors': [], 'messages': [] }
         return WSGIController.__call__(self, environ, start_response)
 
 # Include the '_' function in the public names