Various Shooter-related changes
* Add IsEnabled() to check whether Shooter is running
* Loader shutoff uses IsEnabled() rather than GetSpeed()
  - GetSpeed() is the physical speed of the wheel, so if it moves at all
the cam would start
* Initialize the Shooter in the disabled state. Default commands will
reinforce this
Derp, methods need header declarations, don't they
Implement shutoffs for when Arm is in stowed position
Only disable wrist if elbow is also disabled
Wrist clamping, pending calibration data
Give the shooter time to spin up before enabling the loader