This should allow for creating tests more easily than the python-based server, since we can poke at it from C++ code.
The idea is that each test creates the things it needs (rooms in a certain state, etc) programmatically instead of through
the json files we use for the other tests. This allows us to adapt the test data to each test as needed, without having to copy it around a lot.
- Make an empty message type optional mean "no message"
- Set message type for all actions that send a message through the normal mechanism
- Remove now redundant bool specifying whether a message should be sent
