Invitation emails

I don't like some of the decisions I had to make. Ask about anything specific and I'll explain.

Certain emails were slated to not have "My.jobs on behalf of..." in the closing, but the most recent commit redid that so that all emails have that text. It looks like gmail is also stripping the button css. Since initial saved search emails have buttons, I'm going to assume it might have something to do with the sending host (my work computer) not being production.
![2014-10-24-134314_760x560_scrot](https://cloud.githubusercontent.com/assets/3379265/4773854/22e98314-5ba7-11e4-90e3-18dde9ff770d.png)

All tests pass.