Add ArrayRef overloads to new command classes (#2216)

Also default requirements to {} in all cases for consistency.

wpilibNewCommands/src/main/native/cpp/frc2/command/PIDCommand.cpp

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2019-2020 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.                                                               */
@@ -21,6 +21,18 @@ PIDCommand::PIDCommand(PIDController controller,
   AddRequirements(requirements);
 }
 
+PIDCommand::PIDCommand(PIDController controller,
+                       std::function<double()> measurementSource,
+                       std::function<double()> setpointSource,
+                       std::function<void(double)> useOutput,
+                       wpi::ArrayRef<Subsystem*> requirements)
+    : m_controller{controller},
+      m_measurement{std::move(measurementSource)},
+      m_setpoint{std::move(setpointSource)},
+      m_useOutput{std::move(useOutput)} {
+  AddRequirements(requirements);
+}
+
 PIDCommand::PIDCommand(PIDController controller,
                        std::function<double()> measurementSource,
                        double setpoint, std::function<void(double)> useOutput,
@@ -28,6 +40,13 @@ PIDCommand::PIDCommand(PIDController controller,
     : PIDCommand(controller, measurementSource, [setpoint] { return setpoint; },
                  useOutput, requirements) {}
 
+PIDCommand::PIDCommand(PIDController controller,
+                       std::function<double()> measurementSource,
+                       double setpoint, std::function<void(double)> useOutput,
+                       wpi::ArrayRef<Subsystem*> requirements)
+    : PIDCommand(controller, measurementSource, [setpoint] { return setpoint; },
+                 useOutput, requirements) {}
+
 void PIDCommand::Initialize() { m_controller.Reset(); }
 
 void PIDCommand::Execute() {