Twig tag support

Hello,

This PR adds twig tag `inlinecss` that allows to use css inliner directly in html templates. Real world example:

```html
{% inlinecss 'css/email.css' %}
<!-- HEADER -->
<table class="head-wrap" bgcolor="#2f2f2f">
    <tr>
        <td></td>
        <td class="header container" align="">

            <!-- /content -->
            <div class="content">
                <table bgcolor="#2f2f2f" >
                    <tr>
                        <td><img src="{{ asset('/img/logo.png') }}" /></td>
                        <td align="right"><h6 class="collapse">newsletter</h6></td>
                    </tr>
                </table>
            </div><!-- /content -->

        </td>
        <td></td>
    </tr>
</table><!-- /HEADER -->
{% endinlinecss %}
```

Also fixes minor bugs present in bundle