Galaxykate saveload and heuristics

Implemented save/load (no ui for it yet)
Implemented DNA with mutation rate (needs visualization)
Implemented variable heuristics for arena judging, winner ranking, next generation populating based on that.
Implemented heuristic graphing
Fixed dropdown menus not working (mouseclicks were not propagating correctly)

@dlederle or @mobramaein, can you look at it and then merge?