Split the two command implementations into separate libraries (#2012)

This will allow us at the user code side to determine to include old commands, new commands or both.

wpilibNewCommands/src/main/native/include/frc2/command/CommandBase.h

@@ -0,0 +1,73 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 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/smartdashboard/Sendable.h>
+#include <frc/smartdashboard/SendableHelper.h>
+
+#include <string>
+
+#include <wpi/SmallSet.h>
+#include <wpi/Twine.h>
+
+#include "Command.h"
+
+namespace frc2 {
+/**
+ * A Sendable base class for Commands.
+ */
+class CommandBase : public Command,
+                    public frc::Sendable,
+                    public frc::SendableHelper<CommandBase> {
+ public:
+  /**
+   * Adds the specified requirements to the command.
+   *
+   * @param requirements the requirements to add
+   */
+  void AddRequirements(std::initializer_list<Subsystem*> requirements);
+
+  void AddRequirements(wpi::SmallSet<Subsystem*, 4> requirements);
+
+  wpi::SmallSet<Subsystem*, 4> GetRequirements() const override;
+
+  /**
+   * Sets the name of this Command.
+   *
+   * @param name name
+   */
+  void SetName(const wpi::Twine& name);
+
+  /**
+   * Gets the name of this Command.
+   *
+   * @return Name
+   */
+  std::string GetName() const override;
+
+  /**
+   * Gets the subsystem name of this Command.
+   *
+   * @return Subsystem name
+   */
+  std::string GetSubsystem() const;
+
+  /**
+   * Sets the subsystem name of this Command.
+   *
+   * @param subsystem subsystem name
+   */
+  void SetSubsystem(const wpi::Twine& subsystem);
+
+  void InitSendable(frc::SendableBuilder& builder) override;
+
+ protected:
+  CommandBase();
+  wpi::SmallSet<Subsystem*, 4> m_requirements;
+};
+}  // namespace frc2