T04 updates
The T04 slides are ready for review, @smiths and @niazim3.
The one section of the MIS that I didn't include in any of the slides was the "State Invariants" section. The only module with any state invariants was the Data Module, but I didn't know how to relate that part of the spec to the code. Any ideas for that would be welcome!
Closes #74 (closed).