Patch Notes: Smoother towns, ports and crowds

Performance

Towns, woods and streets cost less to draw. Every patch of trees, plants and lamps used to carry its own small buffer, so drawing it needed a costly state switch first, nearly a thousand times a frame. Still flats now share large buffers, which cuts those switches almost in half, and the picture is the same, triangle for triangle. Measured in the real game at night, the town's frame takes about 14% less main-thread time.
Night-time towns make less garbage. Each lantern's shadow matrices are worked out in place instead of being rebuilt every frame, and the shadow pass stopped creating temporary numbers for every lantern and tree pair. That means fewer garbage-collector pauses, which show up as stutter.
Towns by a harbour are much cheaper. Moored ships no longer rebuild every part every frame, which cost up to 7 ms a frame near a port.
Busy servers stutter less. Other players' name tags, footsteps and sprites make far less garbage, and their sprite art loads in idle time instead of all at once when you turn toward a crowd.
The first spell, the first fight and the first trip to the coast or the sea no longer stall while their shaders compile. Those shaders are now built in the background.
The sky skips drawing stars during the day, when they can't be seen.
On laptops with two graphics cards, the game now asks for the faster one.

With Eye of the Beholder in first person, looking up no longer shows your own body. It now follows the mod's visibility setting, which by default casts your shadow but is never seen.

PERF-CROWD (ported) + PERF-ARENA: a friend's perf passes onto main, and the exterior's frame measured in the real game by @Lattymoy in #758

Full Changelog: app-v0.1.7705...app-v0.1.7720