Add image as signature

I'm used to simply adding an image of my signature to most pdfs. This is most likely not possible for the thesis but for most documents it is sufficient. Especially since most of these are submitted digitally.

We could add an optional variable signature where the user can add a custom piece of code instead of the default empty line to add an image of his signature.

Would you be interested in commits in this direction?

There are other Options

• Allowing the user to point to a image. But this requires additional parameters as width or height and xshift/yshift
• Allowing the user to point to a image that already contains a line and will be right aligned
• Forcing the user to create an image of specific dimensions that will be x\textwidth wide and offset by 1 third of its height or something like that

But these option require a lot more thought and well the other is easier ;)