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/cpp/frc2/command/WaitUntilCommand.cpp

@@ -0,0 +1,20 @@
+/*----------------------------------------------------------------------------*/
+/* 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 "frc2/command/WaitUntilCommand.h"
+
+using namespace frc2;
+
+WaitUntilCommand::WaitUntilCommand(std::function<bool()> condition)
+    : m_condition{std::move(condition)} {}
+
+WaitUntilCommand::WaitUntilCommand(double time)
+    : m_condition{[=] { return frc::Timer::GetMatchTime() - time > 0; }} {}
+
+bool WaitUntilCommand::IsFinished() { return m_condition(); }
+
+bool WaitUntilCommand::RunsWhenDisabled() const { return true; }