Update README.md

added --resX --resY --pause --screenshot_and_close

Update build_shaders.cmd

Update main.c

fix windows render error found by @jjYBdx4IL

thanks @jjYBdx4IL https://github.com/jjYBdx4IL

Update main.c

fix selecting discrete gpu

update vk_utils.c

screenshot fix

Multiple GPU support