[wpilib] Remove PIDController, PIDOutput, PIDSource

Move them to the old commands vendordep so that PIDCommand and PIDSubsystem
continue to work.

This also removes Filter and LinearDigitalFilter.

wpilibc/src/main/native/include/frc/AnalogAccelerometer.h

@@ -8,7 +8,6 @@
 
 #include "frc/AnalogInput.h"
 #include "frc/ErrorBase.h"
-#include "frc/PIDSource.h"
 #include "frc/smartdashboard/Sendable.h"
 #include "frc/smartdashboard/SendableHelper.h"
 
@@ -24,7 +23,6 @@ class SendableBuilder;
  * calibrated by finding the center value over a period of time.
  */
 class AnalogAccelerometer : public ErrorBase,
-                            public PIDSource,
                             public Sendable,
                             public SendableHelper<AnalogAccelerometer> {
  public:
@@ -97,13 +95,6 @@ class AnalogAccelerometer : public ErrorBase,
    */
   void SetZero(double zero);
 
-  /**
-   * Get the Acceleration for the PID Source parent.
-   *
-   * @return The current acceleration in Gs.
-   */
-  double PIDGet() override;
-
   void InitSendable(SendableBuilder& builder) override;
 
  private: