Add SpeedControllerGroup (#362)

wpilibc/src/main/native/include/SpeedControllerGroup.h

@@ -0,0 +1,38 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2016-2017 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 <functional>
+#include <vector>
+
+#include "SpeedController.h"
+
+namespace frc {
+
+class SpeedControllerGroup : public SpeedController {
+ public:
+  template <class... SpeedControllers>
+  explicit SpeedControllerGroup(SpeedController& speedController,
+                                SpeedControllers&... speedControllers);
+
+  void Set(double speed) override;
+  double Get() const override;
+  void SetInverted(bool isInverted) override;
+  bool GetInverted() const override;
+  void Disable() override;
+  void StopMotor() override;
+  void PIDWrite(double output) override;
+
+ private:
+  bool m_isInverted = false;
+  std::vector<std::reference_wrapper<SpeedController>> m_speedControllers;
+};
+
+}  // namespace frc
+
+#include "SpeedControllerGroup.inc"