Moved C++ comments from source files to headers (#1111)

Also sorted functions in C++ sources to match order in related headers.

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

@@ -27,19 +27,85 @@ class AnalogAccelerometer : public ErrorBase,
                             public SendableBase,
                             public PIDSource {
  public:
+  /**
+   * Create a new instance of an accelerometer.
+   *
+   * The constructor allocates desired analog input.
+   *
+   * @param channel The channel number for the analog input the accelerometer is
+   *                connected to
+   */
   explicit AnalogAccelerometer(int channel);
+
+  /**
+   * Create a new instance of Accelerometer from an existing AnalogInput.
+   *
+   * Make a new instance of accelerometer given an AnalogInput. This is
+   * particularly useful if the port is going to be read as an analog channel as
+   * well as through the Accelerometer class.
+   *
+   * @param channel The existing AnalogInput object for the analog input the
+   *                accelerometer is connected to
+   */
   explicit AnalogAccelerometer(AnalogInput* channel);
+
+  /**
+   * Create a new instance of Accelerometer from an existing AnalogInput.
+   *
+   * Make a new instance of accelerometer given an AnalogInput. This is
+   * particularly useful if the port is going to be read as an analog channel as
+   * well as through the Accelerometer class.
+   *
+   * @param channel The existing AnalogInput object for the analog input the
+   *                accelerometer is connected to
+   */
   explicit AnalogAccelerometer(std::shared_ptr<AnalogInput> channel);
+
   ~AnalogAccelerometer() override = default;
 
+  /**
+   * Return the acceleration in Gs.
+   *
+   * The acceleration is returned units of Gs.
+   *
+   * @return The current acceleration of the sensor in Gs.
+   */
   double GetAcceleration() const;
+
+  /**
+   * Set the accelerometer sensitivity.
+   *
+   * This sets the sensitivity of the accelerometer used for calculating the
+   * acceleration. The sensitivity varies by accelerometer model. There are
+   * constants defined for various models.
+   *
+   * @param sensitivity The sensitivity of accelerometer in Volts per G.
+   */
   void SetSensitivity(double sensitivity);
+
+  /**
+   * Set the voltage that corresponds to 0 G.
+   *
+   * The zero G voltage varies by accelerometer model. There are constants
+   * defined for various models.
+   *
+   * @param zero The zero G voltage.
+   */
   void SetZero(double zero);
+
+  /**
+   * Get the Acceleration for the PID Source parent.
+   *
+   * @return The current acceleration in Gs.
+   */
   double PIDGet() override;
 
   void InitSendable(SendableBuilder& builder) override;
 
  private:
+  /**
+   * Common function for initializing the accelerometer.
+   */
   void InitAccelerometer();
 
   std::shared_ptr<AnalogInput> m_analogInput;