Refactored and split out code into separate files for ease of maintenance and future development.
Made planet surfaces generate unique lists of locations to explore.
Now only able to trade at spaceports (this will change in future).
Some tweaks to new user flow.
Added star network and the beginnings of planet generation (i.e what you see when you enter a system for the first time).
Added ability to rename stars and planets.
Added default Deep Space location for all star systems.
Initial version. Contains barebones interface and basic hooks for the future.