Added GPLv3 and Copyright infos to all files. Added a copy of the license to the project.
Prepared a scaffold for the new datamodel from the old one. Have to update the new model to work independently now.
Corrected a mistake in the copyright seciotn. a foobar was not replaced with the program name.
Finished new Model class SM_ModelBackend without Qt MVC Overhead. KISS principle gives me the opportunity to better debug the resulting code. I am pretty sure I do not understand the MVC paradigm of Qt enough to really utilize it successfully, but this is not necessary anyway, because this project is to small to really appreciate the benefits of this framework.
Fixed a little SegV in SM_ModelBackend::clearData(). Double deletion removed.
integrated a model connection into SubnetWidget