[wpilib] Fix multiple motor safety issues (#4784)

Java was missing the motor safety thread entirely
C++ accidentally used a manual reset event, causing the motor safety thread to spin.
C++ PWMMotorController would not feed the watch kitty.
Both languages would call feed() from the StopMotor call, causing some ping ponging.

wpilibc/src/main/native/cpp/motorcontrol/PWMMotorController.cpp

@@ -12,6 +12,7 @@ using namespace frc;
 
 void PWMMotorController::Set(double speed) {
   m_pwm.SetSpeed(m_isInverted ? -speed : speed);
+  Feed();
 }
 
 double PWMMotorController::Get() const {
@@ -31,7 +32,8 @@ void PWMMotorController::Disable() {
 }
 
 void PWMMotorController::StopMotor() {
-  Set(0);
+  // Don't use Set(0) as that will feed the watch kitty
+  m_pwm.SetSpeed(0);
 }
 
 std::string PWMMotorController::GetDescription() const {