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.

wpilibc/src/main/native/include/SolenoidBase.h

@@ -7,7 +7,8 @@
 
 #pragma once
 
-#include "SensorBase.h"
+#include "ErrorBase.h"
+#include "SmartDashboard/SendableBase.h"
 
 namespace frc {
 
@@ -15,9 +16,8 @@ namespace frc {
  * SolenoidBase class is the common base class for the Solenoid and
  * DoubleSolenoid classes.
  */
-class SolenoidBase : public SensorBase {
+class SolenoidBase : public ErrorBase, public SendableBase {
  public:
-  virtual ~SolenoidBase() = default;
   static int GetAll(int module);
   int GetAll() const;