Feature/button alignment

Bugfix for issue https://github.com/echo3/echo3/issues/48 

Futhermore, an interactive JS demo has been included to verify the alignment behaviour:

![image](https://f.cloud.github.com/assets/3050757/761802/1eb7fbe0-e7db-11e2-95d9-49f1acd6dede.png)

P.S.: Please note that I couldn't validate the fix with IE8/9/10 (I tested with Chrome and FF)