Added the functions SDL_JoystickFromPlayerIndex(), SDL_JoystickSetPlayerIndex(), SDL_GameControllerFromPlayerIndex(), and SDL_GameControllerSetPlayerIndex()
It causes the HIDAPI devices to always be opened on enumeration, which causes crashes in the Windows drivers when multiple applications are reading and writing at the same time. We can revisit this after 2.0.10 release.
The Nintendo USB GameCube Adapter has two USB connectors. Black for data
and grey for additional power for rumble. The Wii U and other software
require both cables to use rumble. The rumble is weaker without the
second USB cable. Other than that I don't know if there is any negative
side affects from using rumble with only one cable.
The Nintendo USB GameCube adapter has four controller ports. Return
the port number as 0 to 3 from SDL_JoystickGetPlayerIndex() and
SDL_JoystickGetDevicePlayerIndex().
Note that a single USB device is responsible for all 4 joysticks, so a large
rewrite of the DeviceDriver functions was necessary to allow a single device to
produce multiple joysticks.
