6.2.1 add an arrow to open topic

as in spec

to make it more obvious that there is a topic selector add an arrow 

![unbenannt](https://f.cloud.github.com/assets/4577727/1248970/ab912f7a-2ad7-11e3-91e3-c43cb38582f9.png)



I propose to use
http://fortawesome.github.io/Font-Awesome/icon/external-link-sign/
and rotate it