Add description options for edit-fields and filters

Hi, I'd like to have the option to write some descriptional infos to the edit-fields (and also the filters).

The tought is, that sometimes you need additional infos to fill a field or to explain what the field is all about.

Here is a reallife example:
![editfields_with_desc](https://cloud.githubusercontent.com/assets/6469780/4130879/c2ef89f8-333e-11e4-800d-ba5adad0153f.png)

It's kind of easy to accomplish this; there are only little changes required in the view files and some styling, et voila :)