Terms and Conditions display improvements

When the first element of the rendered terms and conditions is a header element, an unnecessary margin-top is present on that header element. In that case, the margin-top should be removed.

![screen shot 2014-10-19 at 23 58 07](https://cloud.githubusercontent.com/assets/109850/4694899/406c678c-57db-11e4-8aec-2afa14ee3961.png)

I wonder if we'd be better off just introducing a more general rule that removes the margin-top from the first element in Markdown content:

```
 .oae-markdown *:first-child {
     margin-top: 0;
 }
```

I can't immediately think of a scenario where that wouldn't be desired. It would also allow us to remove

```
 .oae-markdown-embedded ol:first-child,
 .oae-markdown-embedded ul:first-child,
 .oae-markdown-embedded p:first-child {
     margin-top: 0;
 }
```

below.

If we go with this, we should make the corresponding changes in Hilary for emails as well.