Codechange: Change the palette rather than the image when recolouring.
Codechange: Remove mega texture (was not working and not used).
Add: 32bpp sprite decoder.
Codechange: Convert legacy 8bpp sprites to 32bpp images using the 0xFF recolour table.
Add: SpriteEncoder source code, description, and a simple decoder.
Add: Generated scanner and parser files (to enable building without having flex and bison).
Add: Input file for the ground tiles, and an example input file.
Feature: Load 32bpp image files into CTH, and store the sprites.
Add: Start for loading free graphics from Lua.
Merge branch 'sdlfreegraphics2' of https://github.com/Alberth289346/CorsixTH into Alberth289346-sdlfreegraphics2

Conflicts:
	CorsixTH/Src/th_gfx_sdl.cpp