Renamed method for consistency

Removed redundant locals

* Split simulator.rb into one file per class

Oopsy

flow! should take an iteration/generational counter

Seems better not to have to mutate the expected value at all

Broke up specs for sanity

Account for flowing water in depth counts

Depth count passes

Honest about the side effects now

Acceptance test passes

Simulator appears to be working now

FlowRules apear to be working now

FlowRules handle clear cut flow cases

Simulator identity stringification