Replaced unicode char for tabbedview menu header.

Use icon instead, because the unicode char didn't work on IE.

**before**
![bildschirmfoto 2013-10-25 um 11 45 27](https://f.cloud.github.com/assets/157533/1406774/374f6dd0-3d5a-11e3-89e2-8f0cf5742b14.png)

**after**
![bildschirmfoto 2013-10-25 um 11 45 13](https://f.cloud.github.com/assets/157533/1406773/373a9f90-3d5a-11e3-8c25-19a1b02615fc.png)