Fix implicitly deleted move constructors (#1954)

These were incorrect and exhibited as warnings on more recent versions of
clang (notably on Mac).

- Use pointers instead of references internally in GenericHID and *Drive
- Leave PIDBase, PIDController, and Resource non-moveable
- Remove the atomic from m_disabled in NidecBrushless
- Make Timer and Trigger copyable as well as moveable
- Implement custom move constructor/assignment for SendableChooserBase

Also comment out some unused variables that caused clang warnings.

wpilibc/src/main/native/include/frc/drive/KilloughDrive.h

@@ -132,9 +132,9 @@ class KilloughDrive : public RobotDriveBase,
   void InitSendable(SendableBuilder& builder) override;
 
  private:
-  SpeedController& m_leftMotor;
-  SpeedController& m_rightMotor;
-  SpeedController& m_backMotor;
+  SpeedController* m_leftMotor;
+  SpeedController* m_rightMotor;
+  SpeedController* m_backMotor;
 
   Vector2d m_leftVec;
   Vector2d m_rightVec;