Sponsorship functionality & UI

PT story https://www.pivotaltracker.com/story/show/78039462

- Add functionality to link sponsor & orphan (i.e. create sponsorship)
- Sponsored orphans shown on sponsor's page
- Sponsorships can be ended by clicking link next to orphan's name on sponsor page
- Establishing a sponsorship marks orphan as 'Sponsored'
- Only Active Unsponsored orphans displayed when creating new sponsorship link
- Only one sponsorship relationship can be established between a sponsor and orphan (enforced in db)

UI is not final as client has sent new specifications
The popup could be seen as annoying or a great feature depending on the client's view. I wouldn't put this in just to pacify me. If the ui is changing it may not be much of an issue.
The experts don't always get it right. 37signals had a lot of problem with this, see these links.
http://bitworking.org/news/I_m_sorry__I_can_t_kiss_it_and_make_it_better_
https://signalvnoise.com/archives2/google_web_accelerator_hey_not_so_fast_an_alert_for_web_app_designers.php