Updates to Model Reference and Bus Traversal

The main changes include fixing bugs related to bus traversal and tracing through Variant Subsystems, and adding support for Model References. The bus traversal system was switched from a recursive to an iterative process to help make future development easier. Various minor fixes relating to bus traversal were also completed: an infinite loop bug fix in Coreach bus traversal, a fix to improper bus traversal memory clearing, an improvement to the word matching system, and removal of extraneous path additions. The Model reference support added in this update uses a recursive process. Other minor updates involving topics including window opening at the end of Reach/Coreach, go/from blocks in masked subsystems, subsystems with multiple in-ports, and support to GUI elements were also made.

Initial GitHub release

v2.2

Update README.md