Errors on unidentified key code.

[aemogie]

Throws an ArrayIndexOutOfBoundsException when any key that GLFW does not support is pressed.
i.e. when keycode -1 is sent, it's still being used to index into the keystateBitfields array.

Steps to reproduce

1. Open any scene
2. On windows, hit a function key without the fn key, so that it does the action, such as increasing/decreasing volume/brightness.

What you expected would happen

For the key to be ignored.

What actually happens

An ArrayIndexOutOfBoundsException is thrown

Error logs

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 400
	at input.Keyboard.resetKeyDownBit(Keyboard.java:64)
	at input.Keyboard.lambda$setupCallbacks$0(Keyboard.java:41)
	at org.lwjgl.glfw.GLFWKeyCallbackI.callback(GLFWKeyCallbackI.java:44)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3397)
	at graphics.Window.showWindow(Window.java:205)
	at util.Engine.showWindow(Engine.java:55)
	at scenes.AudioDemo.main(AudioDemo.java:21)