Issue 173: Exchange transactions

There is an issue about buying rights.

If someone acquires a copyright, this does not necessarily imply that someone else looses it, i.e., that there is only one holder of a Right of type "copyright". If this is the case, my copyright and your copyright on the same text is two different instances.

In this sense, it is not "sold", but I can be paid for resigning from my right and granting you a right.

The question is, if the CRM should deal in such detail with rights and business, or if this would be a compatible extension. In particular, we have no model for exchange businesses of any kind, this was not in the practical scope. But, of course, this is very interesting!