sch-rnd - use cases 
 Block diagram 
Simulink style block diagrams, circuit boards, circuits
with cables, hydraulics and maybe also VHDL. Features
required:
	-  Graphical symbols with pins.
	
-  Possibility to connect pins or more abstract connection points.
	
-  Buses to bunch together like wires in a cable.
	
-  Possibility to assign values to objects.
	
-  The connections will form nets.