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/test/native/cpp/frc2/command/PrintCommandTest.cpp

@@ -0,0 +1,30 @@
+/*----------------------------------------------------------------------------*/
+/* 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include <regex>
+
+#include "CommandTestBase.h"
+#include "frc2/command/PrintCommand.h"
+
+using namespace frc2;
+class PrintCommandTest : public CommandTestBase {};
+
+TEST_F(PrintCommandTest, PrintCommandScheduleTest) {
+  CommandScheduler scheduler = GetScheduler();
+
+  PrintCommand command("Test!");
+
+  testing::internal::CaptureStdout();
+
+  scheduler.Schedule(&command);
+  scheduler.Run();
+
+  EXPECT_TRUE(std::regex_search(testing::internal::GetCapturedStdout(),
+                                std::regex("Test!")));
+
+  EXPECT_FALSE(scheduler.IsScheduled(&command));
+}