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/WaitCommand.h

@@ -0,0 +1,39 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2011-2019 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 <wpi/Twine.h>
+
+#include "frc/commands/TimedCommand.h"
+
+namespace frc {
+
+class WaitCommand : public TimedCommand {
+ public:
+  /**
+   * Creates a new WaitCommand with the given name and timeout.
+   *
+   * @param name    the name of the command
+   * @param timeout the time (in seconds) before this command "times out"
+   */
+  explicit WaitCommand(double timeout);
+
+  /**
+   * Creates a new WaitCommand with the given timeout.
+   *
+   * @param timeout the time (in seconds) before this command "times out"
+   */
+  WaitCommand(const wpi::Twine& name, double timeout);
+
+  virtual ~WaitCommand() = default;
+
+  WaitCommand(WaitCommand&&) = default;
+  WaitCommand& operator=(WaitCommand&&) = default;
+};
+
+}  // namespace frc