Add getRawKeyCode() to KeyPress

Problem: Detect when the user presses Shift + numeric key 3 (not keypad 3) on a US layout

Current solution OSX: Check for # keycode and shift modifier
Current solution Windows: Check for 3 keycode and shift modifier

Also see Shift + number (not from numpad).

It would be nice to have access to the raw unmapped keycodes that the OS provides, so keyboard input can be handled a bit more like in a game engine.