Input system

- Input.as :
justDid, isDoing, hasDone returns either the InputAction or null instead of a boolean value so you can fetch that action and access its properties (value, time ...)
var action:InputAction;

if((action = _ce.input.justDid("up",inputChannel)) != null)
trace("doing up with a value of",action.value);

(specifically good for moving objects with analog input such as virtual joystick or gamepad without having to use getActionValue() which loops into the action list one more time , unecessarily.

if channel is not specified (-1) the first action it encounters with the right name is returned (default is no longer channel 0)

- InputController.as
_updateEnabled added to InputControllers so update is not called when not explicitely asked to.