Smooth frame rates on AMD graphics cards

• Fixed: on AMD graphics cards (seen on an RX 7700 XT on Windows), pages and map walls could drop the game to 1-3 FPS, and the first load of the resource pack could hang for a minute or more on "Reloading ResourceManager", long enough to time a player out. The pack's shader no longer does the work AMD's driver is slow at. Other cards draw exactly as before, at the same speed.
• Important when updating: this version changes how pictures are coloured, in the plugin and the pack together. If you merge MC GUI's pack into Nexo, ItemsAdder or another pack plugin, merge it again from the new build (and rebuild that plugin's pack) after updating. An old merged pack with the new plugin draws pages in the wrong colours.