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/RunCommand.h

@@ -0,0 +1,41 @@
+/*----------------------------------------------------------------------------*/
+/* 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 "CommandBase.h"
+#include "CommandHelper.h"
+
+namespace frc2 {
+/**
+ * A command that runs a Runnable continuously.  Has no end condition as-is;
+ * either subclass it or use Command.WithTimeout() or
+ * Command.WithInterrupt() to give it one.  If you only wish
+ * to execute a Runnable once, use InstantCommand.
+ */
+class RunCommand : public CommandHelper<CommandBase, RunCommand> {
+ public:
+  /**
+   * Creates a new RunCommand.  The Runnable will be run continuously until the
+   * command ends.  Does not run when disabled.
+   *
+   * @param toRun        the Runnable to run
+   * @param requirements the subsystems to require
+   */
+  RunCommand(std::function<void()> toRun,
+             std::initializer_list<Subsystem*> requirements);
+
+  RunCommand(RunCommand&& other) = default;
+
+  RunCommand(const RunCommand& other) = default;
+
+  void Execute();
+
+ protected:
+  std::function<void()> m_toRun;
+};
+}  // namespace frc2