Correct handling of non square images
Improve search for arcade game names
Retrieve other images if no boxart (titlescreen, screenshot)
Changed some arcade rom names to more friendly ones
ImGui is now initialized once at startup and shutdown before
terminating. graphics initialization is independent.
Move more imgui stuff into imgui drivers.
switch: set scaling on external screen to 1.4, same as xbox
UI scaling refactoring.
Refactor imgui backend code into imgui drivers for gl, vk, dx9
Generic GraphicsContext interface for gl/vk/dx9 contexts
Simplify graphics api switching code
dx9, gl(sdl): set swap interval based on monitor refresh rate.