Update LiveWindow to provide continuous telemetry. (#771)

LiveWindow.updateValues() is now called from IterativeRobotBase on every
loop iteration.  Telemetry for all WPILib classes is enabled by default;
it can be disabled for specific classes using LiveWindow.disableTelemetry(),
or all telemetry can be disabled using LiveWindow.disableAllTelemetry().

This necessitated changing the hook methodology into other classes to
be more property-based rather than each class providing multiple functions.
This had the benefit of reducing boilerplate and increasing consistency.

- Remove NamedSendable, add name to Sendable.

- Provide SendableBase abstract class.

- Deprecate LiveWindow addSensor/addActuator interfaces.

- Add LiveWindow support to drive classes.

- Add addChild() helper functions to Subsystem.

- Fix inheritance hierarchy.  Now only sensors inherit from SensorBase.
  Other devices inherit from some combination of SendableBase, ErrorBase, or
  nothing.

wpilibcExamples/src/main/cpp/examples/PacGoat/src/OI.cpp

@@ -13,6 +13,7 @@
 #include "Commands/SetCollectionSpeed.h"
 #include "Commands/SetPivotSetpoint.h"
 #include "Commands/Shoot.h"
+#include "SmartDashboard/SmartDashboard.h"
 #include "Subsystems/Collector.h"
 #include "Subsystems/Pivot.h"
 

wpilibcExamples/src/main/cpp/examples/PacGoat/src/Robot.cpp

@@ -9,6 +9,8 @@
 
 #include <iostream>
 
+#include <Commands/Scheduler.h>
+#include <LiveWindow/LiveWindow.h>
 #include <SmartDashboard/SmartDashboard.h>
 
 DriveTrain Robot::drivetrain;
@@ -60,9 +62,7 @@ void Robot::TeleopPeriodic() {
 	Log();
 }
 
-void Robot::TestPeriodic() {
-	frc::LiveWindow::GetInstance()->Run();
-}
+void Robot::TestPeriodic() {}
 
 void Robot::DisabledInit() {
 	shooter.Unlatch();

wpilibcExamples/src/main/cpp/examples/PacGoat/src/Subsystems/Collector.cpp

@@ -12,14 +12,10 @@
 Collector::Collector()
     : frc::Subsystem("Collector") {
 	// Put everything to the LiveWindow for testing.
-	// XXX: LiveWindow::GetInstance()->AddActuator("Collector", "Roller
-	// Motor", &m_rollerMotor);
-	LiveWindow::GetInstance()->AddSensor(
-			"Collector", "Ball Detector", &m_ballDetector);
-	LiveWindow::GetInstance()->AddSensor(
-			"Collector", "Claw Open Detector", &m_openDetector);
-	LiveWindow::GetInstance()->AddActuator(
-			"Collector", "Piston", &m_piston);
+	AddChild("Roller Motor", m_rollerMotor);
+	AddChild("Ball Detector", m_ballDetector);
+	AddChild("Claw Open Detector", m_openDetector);
+	AddChild("Piston", m_piston);
 }
 
 bool Collector::HasBall() {

wpilibcExamples/src/main/cpp/examples/PacGoat/src/Subsystems/DriveTrain.cpp

@@ -10,20 +10,15 @@
 #include <cmath>
 
 #include <Joystick.h>
-#include <LiveWindow/LiveWindow.h>
 
 #include "../Commands/DriveWithJoystick.h"
 
 DriveTrain::DriveTrain()
     : frc::Subsystem("DriveTrain") {
-	// frc::LiveWindow::GetInstance()->AddActuator("DriveTrain", "Front Left
-	// CIM", &m_frontLeftCIM);
-	// frc::LiveWindow::GetInstance()->AddActuator("DriveTrain", "Front
-	// Right CIM", &m_frontRightCIM);
-	// frc::LiveWindow::GetInstance()->AddActuator("DriveTrain", "Back Left
-	// CIM", &m_backLeftCIM);
-	// frc::LiveWindow::GetInstance()->AddActuator("DriveTrain", "Back Right
-	// CIM", &m_backRightCIM);
+	// AddChild("Front Left CIM", m_frontLeftCIM);
+	// AddChild("Front Right CIM", m_frontRightCIM);
+	// AddChild("Back Left CIM", m_backLeftCIM);
+	// AddChild("Back Right CIM", m_backRightCIM);
 
 	// Configure the DifferentialDrive to reflect the fact that all our
 	// motors are wired backwards and our drivers sensitivity preferences.
@@ -49,16 +44,14 @@ DriveTrain::DriveTrain()
 			(4.0 /*in*/ * M_PI) / (360.0 * 12.0 /*in/ft*/));
 #endif
 
-	LiveWindow::GetInstance()->AddSensor(
-			"DriveTrain", "Right Encoder", m_rightEncoder);
-	LiveWindow::GetInstance()->AddSensor(
-			"DriveTrain", "Left Encoder", m_leftEncoder);
+	AddChild("Right Encoder", m_rightEncoder);
+	AddChild("Left Encoder", m_leftEncoder);
 
 // Configure gyro
 #ifndef SIMULATION
 	m_gyro.SetSensitivity(0.007);  // TODO: Handle more gracefully?
 #endif
-	LiveWindow::GetInstance()->AddSensor("DriveTrain", "Gyro", &m_gyro);
+	AddChild("Gyro", m_gyro);
 }
 
 void DriveTrain::InitDefaultCommand() {

wpilibcExamples/src/main/cpp/examples/PacGoat/src/Subsystems/Pivot.cpp

@@ -7,8 +7,6 @@
 
 #include "Pivot.h"
 
-#include <LiveWindow/LiveWindow.h>
-
 Pivot::Pivot()
     : frc::PIDSubsystem("Pivot", 7.0, 0.0, 8.0) {
 	SetAbsoluteTolerance(0.005);
@@ -20,16 +18,10 @@ Pivot::Pivot()
 #endif
 
 	// Put everything to the LiveWindow for testing.
-	frc::LiveWindow::GetInstance()->AddSensor(
-			"Pivot", "Upper Limit Switch", &m_upperLimitSwitch);
-	frc::LiveWindow::GetInstance()->AddSensor(
-			"Pivot", "Lower Limit Switch", &m_lowerLimitSwitch);
-	// XXX: frc::LiveWindow::GetInstance()->AddSensor("Pivot", "Pot",
-	// &m_pot);
-	// XXX: frc::LiveWindow::GetInstance()->AddActuator("Pivot", "Motor",
-	// &m_motor);
-	frc::LiveWindow::GetInstance()->AddActuator(
-			"Pivot", "PIDSubsystem Controller", GetPIDController());
+	AddChild("Upper Limit Switch", m_upperLimitSwitch);
+	AddChild("Lower Limit Switch", m_lowerLimitSwitch);
+	AddChild("Pot", m_pot);
+	AddChild("Motor", m_motor);
 }
 
 void InitDefaultCommand() {}

wpilibcExamples/src/main/cpp/examples/PacGoat/src/Subsystems/Pneumatics.cpp

@@ -7,12 +7,11 @@
 
 #include "Pneumatics.h"
 
-#include <LiveWindow/LiveWindow.h>
+#include <SmartDashboard/SmartDashboard.h>
 
 Pneumatics::Pneumatics()
     : frc::Subsystem("Pneumatics") {
-	frc::LiveWindow::GetInstance()->AddSensor(
-			"Pneumatics", "Pressure Sensor", m_pressureSensor);
+	AddChild("Pressure Sensor", m_pressureSensor);
 }
 
 /**

wpilibcExamples/src/main/cpp/examples/PacGoat/src/Subsystems/Shooter.cpp

@@ -7,20 +7,13 @@
 
 #include "Shooter.h"
 
-#include <LiveWindow/LiveWindow.h>
-
 Shooter::Shooter()
     : Subsystem("Shooter") {
 	// Put everything to the LiveWindow for testing.
-	frc::LiveWindow::GetInstance()->AddSensor(
-			"Shooter", "Hot Goal Sensor", &m_hotGoalSensor);
-	frc::LiveWindow::GetInstance()->AddSensor("Shooter",
-			"Piston1 Reed Switch Front ",
-			&m_piston1ReedSwitchFront);
-	frc::LiveWindow::GetInstance()->AddSensor("Shooter",
-			"Piston1 Reed Switch Back ", &m_piston1ReedSwitchBack);
-	frc::LiveWindow::GetInstance()->AddActuator(
-			"Shooter", "Latch Piston", &m_latchPiston);
+	AddChild("Hot Goal Sensor", m_hotGoalSensor);
+	AddChild("Piston1 Reed Switch Front ", m_piston1ReedSwitchFront);
+	AddChild("Piston1 Reed Switch Back ", m_piston1ReedSwitchBack);
+	AddChild("Latch Piston", m_latchPiston);
 }
 
 void Shooter::InitDefaultCommand() {