Updates ferris-users plugin to work in ferris v2.2.0. 

(Previously it didn't work out of the box). Also it now it no longer needs the ferris-csrf plugin as a dependency, as it now uses Ferris' now-built-in CSRF component.

Right now I'm trying to work on a ferris-boilerplate. Would love to collaborate, and it would be nice to be able to track any changes to gae-boilerplate to keep plugins like this up-to-date and functional.