Add ngFsCouplePortrait directive for use in the new add flow.

@lambertsteven Can you take a look at this and merge it? This is the new ngFsCouplePortrait directive. There's also a pull request in fs-styles for the matching styles. Thanks.
I haven't used it in a place that modifies the data that goes in. The watch fires when the directive loads, but it wouldn't fire again if the data was updated.