Reportback Flag form - front end

Heaven help me I wrote jQuery today. :christmas_tree: 

Refs #3564.

Adds form elements for the Flag reportback form, which are only displayed when "flagged" is checked.

Doesn't actually write any values yet, as the first priority is to get a prototype up for campaigns team to test.

![screen shot 2014-12-09 at 3 42 11 pm](https://cloud.githubusercontent.com/assets/1236811/5365443/faefa73a-7fb9-11e4-9dc6-819e6339b6d0.png)
Maybe better to provide the selector argument to `parent()`?