Allow input modules to supply default assignments considering connected peripherals

[cuavas]

The problem is that analog axes on game controllers are a complete mess:

• Flight simulation controls report roll = X, pitch = Y, throttle = Z, yaw = rZ.
• The de facto standard for HID game pads is left stick X = X, left stick Y = Y, right stick X = Z, right stick Y = rZ (Z and rZ are reversed compared to flight simulation controls).
• Xinput controllers read via DirectInput report left stick X = X, left stick Y = Y, right stick X = rX, right stick Y = rY, combined triggers = Z (like they went against the grain to make life hard).

There’s no sensible set of defaults that suits even just these three kinds of controllers. The input provider modules need to be able to use heuristics to supply defaults depending on the connected devices.

Just calling through to input provider modules when the OSD interface object customises the input list won’t work properly, because input device numbers get remapped when the controller configuration file is loaded. It has to happen after input device numbers are remapped, but before defaults from the controller configuration file are applied.

• [X] SDL
  • [X] Game controller
  • [X] Joystick
• [ ] Xinput
  • [x] Gamepad
  • [ ] Driving controls
  • [x] Flight stick
  • [x] Guitar
  • [X] Drum kit
  • [x] Turntable
  • [X] Keyboard
• [x] DirectInput

[cuavas]

d4589e0b29d6085072ff635d87c3d95c21813a58 implements most of this. Mappings for flight and driving controls are based on assumptions for the most part as most MAME users seem to have traditional game controllers and rhythm/music game peripherals. XInput driving controls will probably have bad default assignments, I haven’t thought them through properly.