Lambda works

Ok here is the basic deal.  While the :url option was nice it was only worked in when when you had a default cas setup.  If there was anything odd it would break.  Also the use of the overriding initialize method broke using the lambda method of the setting up the authentication dynamically. This also broke the steps Omniauth says to use in updating a strategy to 1.0 in https://github.com/intridea/omniauth/wiki/Adapting-strategies-for-1.0 .  I needed to use the lambda in setting up a CAS authentication plugin for Discourse.  The current version of omni_auth would only work at startup and would not update if you you changed settings in the app.  This would not be to bad except that Discourse supports multisite (hosting multiple domains with one code tree) and needs to use different settings for different site.