SOL by tan.go

## Fixes
- FOV effects (sprinting, speed, slowness, spyglass) did not reach the world. Sol now uses the projection Minecraft actually renders the world with.
- Switching graphics to or from Fast left parts of the world invisible until restaring the game. Now the world is re-meshed in place, nearest sections first, and the old geometry stays visible until each section is replaced.

## New
- R key (rebindable, Controls > Sol): now reloads the world from the center.
- The world stays on screen during a reload until the world is fully reloaded. An earlier internal version did; on a server that could act or work like x-ray.