Reset subgraph variables and local variables

It would be nice if you could reset subgraph variables and also introduce true local variables. That is, you dont need to reset the variables because it just does everytime the subgraph is used. Its scope starts and ends within the subgraph - on exit its deleted.

Without these two you get weird sideeffects and have to manually reset variables which is adding a lot of extra work for something that seems it should be already there for a coding logic tool.