TODO list in random order:

• Clean-up and simplification of code
• New design using C++20, templates, modules, coroutines, etc.
• Use C++11 random generators
• More and better examples
• English documentation
• New/better calendar implementations (SNOOPY)
• Test suite (unit tests, more test models)
• Graphical user interface ?
• Option: use GSL/other library as backend
• Create non-global SimulationContext (for nested simulation)
• ...
• Goal: SIMLIB/C++ should be simple (it is for educational use)