Ignore quotes when converting special characters to HTML entities

Otherwise when you execute this command:
```php
Role::create( array('name' => 'admin') );
```

This unreadable SQL log appears:
```sql
insert into &amp;quot;roles&amp;quot; (&amp;quot;name&amp;quot;, &amp;quot;updated_at&amp;quot;, &amp;quot;created_at&amp;quot;) values ('admin', '2013-09-09 13:27:43', '2013-09-09 13:27:43') returning &amp;quot;id&amp;quot;
```