Avoiding cut-off of headings with fixed launcher on Ubuntu

Hi,

today I've visited the GeoExt2 website and with a fixed launcher on Ubuntu the h1 headings are cut off. 
![geoextsitewithoutspan12](https://f.cloud.github.com/assets/2471172/2399657/0e6837e4-aa01-11e3-8490-684297e6cdbe.png)

For that reason I've added Bootstraps "span12" class to the headings.
![geoextsitewithspan12](https://f.cloud.github.com/assets/2471172/2399699/ad3b0a36-aa01-11e3-8229-cb562a424c25.png)

Hope you like it!

Cheers,
Matthias