Add spacing around paragraphs within LegislativeLists

This matches styling in place on Whitehall and is what the PO has requested.

Govspeak:

```
$LegislativeList
* 1. Body
* 2. With

* 3. Line breaks
* 4. Like this
```

## Whitehall styling
![whitehall](https://dl.dropboxusercontent.com/u/39836361/legislativelist/whitehall.png)

## Manuals frontend before/after
![m-f-before](https://dl.dropboxusercontent.com/u/39836361/legislativelist/manuals-frontend-before.png) ![m-f-after](https://dl.dropboxusercontent.com/u/39836361/legislativelist/manuals-frontend-after.png)