This adds functions to query the keymap:
* SDL_GetCurrentKeymap()
* SDL_GetKeymapKeycode()
* SDL_GetKeymapScancode()
* SDL_ReleaseKeymap()
and these are distinct from the function to query the event keycode associated with a scancode, which might be affected by SDL_HINT_KEYCODE_OPTIONS.
Also added an SDL_bool parameter to SDL_GetKeyName() and SDL_GetKeyFromName() to enable upper case handling of the name.
c298a3749b