encode Reply-To correctly

@buchi @maethu can you take a look at this this fixes the mess with the reply-to address in the feedback forms.
Before:
![unbenannt2](https://f.cloud.github.com/assets/358342/1643971/63569fb8-58d8-11e3-917e-7439fb0558e7.JPG)

After:
![unbenannt-1](https://f.cloud.github.com/assets/358342/1643970/634137c2-58d8-11e3-9a5b-0a8fba508cc9.JPG)