FlxGamepad: support circular deadzones as well by adding deadZoneMode, closes #1176
FlxGamepadAxes -> FlxGamepadAnalogueStick
Moved FlxGamepadAnalogStick into FlxGamepad.hx, Analogue -> Analog
Merge pull request #1177 from Gama11/gamepadDeadzoneFix

FlxGamepad: support circular deadzones as well by adding deadZoneMode, closes #1176