Missing / stange translations

https://github.com/4teamwork/ftw.subsite/blob/master/ftw/subsite/portlets/teaserportlet.py

- In my opinion there should be "Titel" and "Beschreibung" the translations, like in default content types.
- Help text for title and description can be removed if it doesn't say more than the label.
 
![Bildschirmfoto 2013-04-22 um 08 44 21](https://f.cloud.github.com/assets/157533/407858/465bf94e-ab18-11e2-93fa-db24977ccc83.png)