Nest trig_dist() in rl_dist() instead of replicating the implementation.
Marshall info about the current square at the start of drawsq() instead of calling the same methods multiple times.
Add a caching accessor for whether the player has active night vision.
Use new accessor to test for presence of nightvision tech.
Add invalidation hook to player that is called every action.
Merge PRs #1474, #1470, #1467 - drawing efficiency boosts
Const a few more (required) item methods