Removed the Viewer class and associated functions and exceptions.
Provided empty argument list defaults for InvokeFunction.
Added nicer viewer annotations.
Fixed write attribute access types.
1l=[(0,10),(10,20)] 2y=23 3fora,binl: 4foriina,b: 5x=i 6else:# NOTE: Need to support StopIteration! 7x=y 8else: 9a=b