Show member’s statement on card hover

**WIP** Closes #2054

### Todo
- [ ] Fetch statement for givers and receivers
- [ ] Styling changes to match Gittip
- [ ] Create appropriate changes to schema
- [ ] Cross browser/device testing

![screen shot 2014-03-21 at 3 35 16 pm](https://f.cloud.github.com/assets/65468/2487115/03ccfee2-b130-11e3-9fff-70aaac8e4d54.png)