Fix issue #8: Add support for TagBar

Turned out to be quite easy to integrate with TagBar. Works like a charm!

It looks like this:

![Bildschirmfoto 2013-04-14 um 16 59 28](https://f.cloud.github.com/assets/115889/378070/f8d241b0-a513-11e2-802e-d4419aac586d.png)