It seems like the login and logout urls are used in a lot of places.  It might be worthwhile to make values an instance variable and to initialize it with common values in BaseHandler.dispatch() so that we don't have this repeated code.

If you don't want to do this now, that's totally fine -- I'm probably going to be changing up the base handler a bit in my next change in any case (can you add a TODO so that I remember to do it, though?).  If you do want to make this change, then you can see how I did [CsrfHandler.dispatch()](https://github.com/samking/code-the-change-projects/blob/samking-base-handler/helpers/csrf.py).  This should be mostly the same -- initialize values to an empty dict in __init__, and if it's a get request, dispatch() would populate it with the login/logout urls.

I think that dispatch() is the only way to get common code for all of our handlers without having to do something like call super(FooHandler, self).get() everywhere.