Add support for ticket prices

[TheRealMurmel]

Hi,

I did some research on how to retrieve ticket prices using the DB api. In order to make the information available to others, I created a small sample project to demonstrate the required requests:

https://github.com/TheRealMurmel/py-bahn-api

derhuerst suggested in public-transport/hafas-client/issues/291 to integrate this into pyhafas.

I could give it a try, if you are interested in this feature.

[1Maxnet1]

I would be interested in that feature as well. Could offer some help in implementation and/or testing :)