raylib 6.0 adds CPU-only software renderer and new memory framebuffer backend

raylib 6.0 introduces a software renderer backend, allowing the library to run fully on a CPU without requiring GPU hardware. This release also includes a new memory framebuffer backend for headless 2D and 3D rendering, supporting direct frame export to images. Additional updates include a direct Win32 backend and a redesigned system for fullscreen modes and high-DPI scaling.