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/PrintCommand.h

@@ -0,0 +1,35 @@
+/*----------------------------------------------------------------------------*/
+/* 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 <wpi/Twine.h>
+#include <wpi/raw_ostream.h>
+
+#include "CommandHelper.h"
+#include "InstantCommand.h"
+
+namespace frc2 {
+/**
+ * A command that prints a string when initialized.
+ */
+class PrintCommand : public CommandHelper<InstantCommand, PrintCommand> {
+ public:
+  /**
+   * Creates a new a PrintCommand.
+   *
+   * @param message the message to print
+   */
+  explicit PrintCommand(const wpi::Twine& message);
+
+  PrintCommand(PrintCommand&& other) = default;
+
+  PrintCommand(const PrintCommand& other) = default;
+
+  bool RunsWhenDisabled() const override;
+};
+}  // namespace frc2