* Enabled GDB server, compile fix for MSVC, added GDB option to config
* GDB - 'vMustReplyEmpty' should not be explicitly handled, it is a test for how the target responds to unknown vpackets (which was incorrect)
* GDB wait for debugger option to allow debugging from bootstrap, and Event::Resume moved after renderer init so agent.interrupt() can pause the renderer
* Draw "Waiting for debugger", and fixed UI not rendering last frame before a state change
* Fixed GDB regs/mem endianness
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.
Xphalnos