Fix pretty printing of external trajectories
Tests passing again after a bunch of changes
Change a few things about how threats are represented
Rename ship to board
Threats have their own speed
Refactoring for simplicity.

My first approach seems too cumbersome. Instead I'm going to change
to have a map of objects which can be filtered by properties, so
that I can avoid making changes to nested map structures.
Some basic tests and code for players, movements and tracks
Add shields
Add reactors
Use *name* convention
Add fuel rods
Add :type, fix track definitions
Add find-by-type to find all objects of a certain type in the game
Update README to mention The New Frontier
Store all game data in the same format
Can add threats with (add-threat game threat-id track-id turn)