Include links to online doc in help text of single functions

[hagenw]

It might be a good idea to include links to corresponding sections in the online documentation at the end of the header comments of single functions.

The problem is that most of the links are longer than 80 characters and fit not very well into the help text. For example:

http://matlab.sfstoolbox.org/en/latest/binaural-simulations/#frequency-response-of-your-spatial-audio-system

Before including the links it would be nice to find a good way to shorten them.