<pre> elements support

<pre> elements do not render as in pure HTML.
White spaces and end of line characters should all be kept, but they aren't.
For example:
```
{template test()}
<pre>
      one
   two
three
</pre>

{/template}

module.exports = {
  template: test,
  data: []
};

```
Somehow linked to issue #68 and a general problem around these characters.
```
