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.

wpilibOldCommands/src/main/native/include/frc/commands/InstantCommand.h

@@ -0,0 +1,93 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2016-2019 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 <functional>
+
+#include <wpi/Twine.h>
+
+#include "frc/commands/Command.h"
+#include "frc/commands/Subsystem.h"
+
+namespace frc {
+
+/**
+ * This command will execute once, then finish immediately afterward.
+ *
+ * Subclassing InstantCommand is shorthand for returning true from IsFinished().
+ */
+class InstantCommand : public Command {
+ public:
+  /**
+   * Creates a new InstantCommand with the given name.
+   *
+   * @param name The name for this command
+   */
+  explicit InstantCommand(const wpi::Twine& name);
+
+  /**
+   * Creates a new InstantCommand with the given requirement.
+   *
+   * @param subsystem The subsystem that the command requires
+   */
+  explicit InstantCommand(Subsystem& subsystem);
+
+  /**
+   * Creates a new InstantCommand with the given name.
+   *
+   * @param name      The name for this command
+   * @param subsystem The subsystem that the command requires
+   */
+  InstantCommand(const wpi::Twine& name, Subsystem& subsystem);
+
+  /**
+   * Create a command that calls the given function when run.
+   *
+   * @param func The function to run when Initialize() is run.
+   */
+  explicit InstantCommand(std::function<void()> func);
+
+  /**
+   * Create a command that calls the given function when run.
+   *
+   * @param subsystem The subsystems that this command runs on.
+   * @param func      The function to run when Initialize() is run.
+   */
+  InstantCommand(Subsystem& subsystem, std::function<void()> func);
+
+  /**
+   * Create a command that calls the given function when run.
+   *
+   * @param name   The name of the command.
+   * @param func   The function to run when Initialize() is run.
+   */
+  InstantCommand(const wpi::Twine& name, std::function<void()> func);
+
+  /**
+   * Create a command that calls the given function when run.
+   *
+   * @param name      The name of the command.
+   * @param subsystem The subsystems that this command runs on.
+   * @param func      The function to run when Initialize() is run.
+   */
+  InstantCommand(const wpi::Twine& name, Subsystem& subsystem,
+                 std::function<void()> func);
+
+  InstantCommand() = default;
+  virtual ~InstantCommand() = default;
+
+  InstantCommand(InstantCommand&&) = default;
+  InstantCommand& operator=(InstantCommand&&) = default;
+
+ protected:
+  std::function<void()> m_func = nullptr;
+  void _Initialize() override;
+  bool IsFinished() override;
+};
+
+}  // namespace frc