representing the active state of the joystick after calibration

that it should also end joystick polling when it becomes inactive. Otherwise we
may have stray threads hangin around.

Separate startJoystick from enableJoystick. Just because the joystick is not enabled doesn't mean that we don't want to be able to monitor its behavior

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

This reverts commit 0507fb9b.