Parse Style CSS

Support text/css style type in SVG parser/renderer/serializer, for example:
```
<style type="text/css">
        .mystyle{fill:none;stroke:#000000;stroke-width:1.5;stroke-miterlimit:10;}
</style>
<rect class="mystyle" x="48.2" y="54" class="st0" width="16.8" height="91.8"/>
```