Replace deprecated API usage in C++ examples

Since there is a new version of GearsBot using the new command-based
API, the old GearsBot is just removed.

PR #1842 is being included to verify this PR is correct.

wpilibcExamples/src/main/cpp/examples/GearsBot/include/commands/SetDistanceToBox.h

@@ -1,44 +0,0 @@
-/*----------------------------------------------------------------------------*/
-/* Copyright (c) 2017-2018 FIRST. All Rights Reserved.                        */
-/* Open Source Software - may be modified and shared by FRC teams. The code   */
-/* must be accompanied by the FIRST BSD license file in the root directory of */
-/* the project.                                                               */
-/*----------------------------------------------------------------------------*/
-
-#pragma once
-
-#include <frc/PIDController.h>
-#include <frc/PIDOutput.h>
-#include <frc/PIDSource.h>
-#include <frc/commands/Command.h>
-
-/**
- * Drive until the robot is the given distance away from the box. Uses a local
- * PID controller to run a simple PID loop that is only enabled while this
- * command is running. The input is the averaged values of the left and right
- * encoders.
- */
-class SetDistanceToBox : public frc::Command {
- public:
-  explicit SetDistanceToBox(double distance);
-  void Initialize() override;
-  bool IsFinished() override;
-  void End() override;
-
-  class SetDistanceToBoxPIDSource : public frc::PIDSource {
-   public:
-    virtual ~SetDistanceToBoxPIDSource() = default;
-    double PIDGet() override;
-  };
-
-  class SetDistanceToBoxPIDOutput : public frc::PIDOutput {
-   public:
-    virtual ~SetDistanceToBoxPIDOutput() = default;
-    void PIDWrite(double d) override;
-  };
-
- private:
-  SetDistanceToBoxPIDSource m_source;
-  SetDistanceToBoxPIDOutput m_output;
-  frc::PIDController m_pid{-2, 0, 0, &m_source, &m_output};
-};