The new image formats are loaded with stb_image, and the textures are saved with stb_image_write.
https://github.com/nothings/stb
You can now load GIFs (not animated), PSD, TGA, HDR, PIC and PNM.
The texture loading still uses sfil for JPEG, PNG, and BMP. You can force the use of stbi by loading with
the "type" argument in texture.load() set to 242 (or anything 5<x<250, but 242 is a good value).
The :save() formats are PNG and BMP only.
