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.

wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/templates/commandbased/Robot.java

@@ -10,7 +10,6 @@ package edu.wpi.first.wpilibj.templates.commandbased;
 import edu.wpi.first.wpilibj.TimedRobot;
 import edu.wpi.first.wpilibj.command.Command;
 import edu.wpi.first.wpilibj.command.Scheduler;
-import edu.wpi.first.wpilibj.livewindow.LiveWindow;
 import edu.wpi.first.wpilibj.smartdashboard.SendableChooser;
 import edu.wpi.first.wpilibj.smartdashboard.SmartDashboard;
 import edu.wpi.first.wpilibj.templates.commandbased.commands.ExampleCommand;
@@ -119,6 +118,5 @@ public class Robot extends TimedRobot {
 	 */
 	@Override
 	public void testPeriodic() {
-		LiveWindow.run();
 	}
 }