Added icon to toggle simplelayout controls

@Tschanzt 
![bildschirmfoto 2014-02-13 um 11 09 22](https://f.cloud.github.com/assets/157533/2158654/21affe7e-9497-11e3-93e7-237a78e7da56.png)
![bildschirmfoto 2014-02-13 um 11 09 28](https://f.cloud.github.com/assets/157533/2158655/21b025d4-9497-11e3-8464-412f6b3530d9.png)