Gamepad wrong min value for triggers

[edumeneses]

The gamepad triggers show wrong nim values: -1 instead of 0

This is problematic when relying on automatic ranging, e.g., mapping the gamepad trigger (range 0 to 1) to control frequency in a shader or synth (range from 0 to 200 Hz).

Tested with a PS4 controller (gamepad mode activated).

[jcelerier]

https://github.com/ossia/libossia/blob/master/src/ossia/protocols/joystick/game_controller_protocol.cpp#L48 all of this is defined in this file if you want to check

[edumeneses]

The problem is on line 104; the triggers are on the axes category in SDL and shared the same min and Max in score. This is not a priority. I'll try to fix this earlier next week.