SDL Input

[arves100]

The code was designed to support only mouse and keyboard, after the switch to a basic SDL window system, the input would eventually need to be converted.
An idea would be to use specifically scankeys and have the reply system report them accordingly, unfortunatelly, this would also mean breaking the reply files (and there might be no way to restore them).
As I would like to keep compatibility with as much things as possible, while adding support for controller devices as well (such as joystick and gamepads), here's what needs to be done:

• Convert DirectInput code with SDL2 input code (oldgen_lnxa/master can help with this)
• Implement an Action-like approach to associate a specific device with an action, this can help to have support for both keyboard and joystick at the same time.
• Add new API to cover with joystick and gamepad support
• Create a new reply format that will register action inputs and the device that comes with it (either a keyboard, joystick, etc...)
• Implement testing code for touch as well, this would be a good step for porting under Android/iOS or PC with touchscreens