CLI output to disk

[ptheywood]

For F1 parity need to be able to write out state lists to disk every N iterations, when simulate is used.

via the config / cli:

• specify format
• specify location (Possibly optional, using working dir /next to input if specified?)
• specify frequency (0 means never, 1 = every iteration, 100 is every 100 iterations etc.)

Should default to being off (much better performance)