C++ Keyboard InputManager v1.0.0
This expands on @SPQR 's 'NON BLOCKING UNBUFFERED CONSOLE INPUT in C'. This is used to be able to whitelist and blacklist certain keys from being outputted in the GetPressedKey function. In a much more user friendly and readable way.
Make sure you call Update() every frame.
If no keys have been whitelisted, all keys will become whitelisted.
Due to limitations with getch(), only one input can be detected at once.