FileType parser arguments for output should append.

Because when there's a "lost the point" RollEvent, we have no idea by just looking at this single event what the point value was that we just lost.

Give cdc simulate an option to output the Probability Density Function info as JSON, then add cdc plot command that can plot data given this JSON.

• What happens when empty
• What happens when getting single item
• What order multiple items are returned in
• What happens when wanting more items than the list contains

As it is now, right now the actual math happens in simulate.py, which is a little weird for testing. It's there because the BinOp may have a left or right side that is more complex than a simple int or float or list, and needs to turn VarIds and ListIds to their actual values.

What would probably be more correct would be to move UserDefinedStrategy._reduct_binop's logic to BinOp in stratlang.py and pass the function all the strategy state it would ever need.