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/WaitCommand.h

@@ -0,0 +1,51 @@
+/*----------------------------------------------------------------------------*/
+/* 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 <units/units.h>
+#include <wpi/Twine.h>
+
+#include "CommandBase.h"
+#include "CommandHelper.h"
+#include "frc2/Timer.h"
+
+namespace frc2 {
+/**
+ * A command that does nothing but takes a specified amount of time to finish.
+ * Useful for CommandGroups.  Can also be subclassed to make a command with an
+ * internal timer.
+ */
+class WaitCommand : public CommandHelper<CommandBase, WaitCommand> {
+ public:
+  /**
+   * Creates a new WaitCommand.  This command will do nothing, and end after the
+   * specified duration.
+   *
+   * @param duration the time to wait
+   */
+  explicit WaitCommand(units::second_t duration);
+
+  WaitCommand(WaitCommand&& other) = default;
+
+  WaitCommand(const WaitCommand& other) = default;
+
+  void Initialize() override;
+
+  void End(bool interrupted) override;
+
+  bool IsFinished() override;
+
+  bool RunsWhenDisabled() const override;
+
+ protected:
+  Timer m_timer;
+
+ private:
+  units::second_t m_duration;
+};
+}  // namespace frc2