Fix dependency loop between Models and Minimizer

[phbasler]

Currently Models depends on Minimizer and Minimizer on Models.

Models only depends on Minimizer because of the function CheckImplementation , which is only used in the src/prog/Test.cpp.

This function mostly calls free functions and some member variables. We should try to move this function outside of the Models library, maybe to a new library which then can depend on Models and Minimizer.