Instead of `gdi_fabulous` introduced some bit flags for enabling/disabling features individually. Mainly for testing and benchmarking purposes of these features until we decide the best implementation for each of them. So they are enabled by setting flags with `Clay_Win32_SetRendererFlags()` in user code (demo in this case)
CreateWindow(Ex) size parameters actually accepts outer window dimensions containing caption and border, which we can calculate with AdjustWindowRect by giving client size window dimensions.
