Implement sponsor feature and add adiitonal scenarios for earlier features

Part of PT story https://www.pivotaltracker.com/story/show/76232594

- add more tests to admin users feature
- add additional scenario to partner featue
- added sponsor feature 
- fix delete links being show for sponsors by active admin
- added linked name to sponsor index view
- refactored authenticated user step into background
I did think the same but I also wanted a test that could go through the unhappy path as a running example that all of the machinery (webkit, switching contexts, and calling the unhappy path worked).
For me it felt like a good comprimise