Blockquote class not present

Hi, thanks for this great theme.

When writing:

`> Some stuff that someone said`

The output is:
```
<blockquote>
Some stuff that someone said
</blockquote>
```

It should be
```
<blockquote class="blockquote">
Some stuff that someone said
</blockquote>
```

To be properly formatted with Bootstrap. How and where should this be implemented?