did not add the additional code to use unauthenticated IPSC with the
log mixin. Added it blind - as in I've not tested it yet. If someone
finds this and tests it BEFORE I do, please let me know if it works.
As of now, dmrlink.py is only a behind the scenes worker... It's just
the base class to take care of link establishment and maintenance.
Applications, such as bridging or logging will now be in their own
files and inherit from dmrlink.py