Add Inverted Light Bulb
Add Inverted Tile Light
Image checksum threadpool now runs in the background during startup
Shutdown image checksum threadpool after finishing computation
Add server config option for 'loadAllImagesOnStartup', defaulted to true - this computes the checksums of every image so clients don't request them
Add server config option for 'loadImagesThreadpoolSize', defaulted to 20 (Set to lower values to take up less memory during server boot, set to higher to compute checksums faster)
Add better shader compatibility for flashlight
Fixed server lag that could occur when loading into a chunk with many photos for the first time
Add whitelist for seedspreader