cpp_headers: Renamed C++ headers from .h -> .hpp

To make room for UPM C and C++ sensor code to coexist, all UPM
C++ headers have been renamed from h -> hpp.  This commit contains
updates to documentation, includes, cmake collateral, examples, and
swig interface files.

    * Renamed all cxx/cpp header files which contain the string
    'copyright intel' from .h -> .hpp (if not already hpp).

    * Replaced all references to .h with .hpp in documentation,
    source files, cmake collateral, example code, and swig interface
    files.

    * Replaced cmake variable module_h with module_hpp.

    * Intentionally left upm.h since this file currently does not
    contain code (documentation only).

Signed-off-by: Noel Eck <noel.eck@intel.com>

src/dfrph/dfrph.hpp

@@ -0,0 +1,143 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2015 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#pragma once
+
+#include <iostream>
+#include <string>
+#include <mraa/aio.hpp>
+
+namespace upm {
+  /**
+   * @brief DFRobot pH sensors
+   * @defgroup dfrph libupm-dfrph
+   * @ingroup dfrobot liquid analog
+   */
+
+  /**
+   * @library dfrph
+   * @sensor dfrph
+   * @comname DFRobot pH Sensors
+   * @type liquid
+   * @man dfrobot 
+   * @web http://www.dfrobot.com/index.php?route=product/product&product_id=1110
+   * @con analog
+   *
+   * @brief API for the DFRobot pH Sensors
+   *
+   * This sensor family returns an analog voltage proportional to the
+   * acidity or alkalinity of a liquid -- it's pH value.
+   *
+   * This driver was developed using the DFRobot Analog pH meter and
+   * the DFRobot Analog pH Meter Pro.
+   *
+   *
+   * Calibration instructions, taken and slightly reworded from the
+   *  DFRobot wiki at:
+   *  http://dfrobot.com/wiki/index.php/PH_meter%28SKU:_SEN0161%29
+   *
+   *  1) Connect equipment: the pH electrode is connected to the BNC
+   *  connector on the pH meter board, and then the pH meter board is
+   *  connected to the analog port 0 of the controller. When the
+   *  controller gets power, you will see the blue LED on board is on.
+   *
+   *  2) Put the pH electrode into the standard solution whose pH
+   *  value is 7.00.  Run the dfrph example and note the pH output
+   *  value.  Compare the value with 7.00, and calculate the
+   *  difference.  This is the value you should supply to the
+   *  setOffset() method.
+   *
+   *  3) Put the pH electrode into the pH standard solution whose
+   *  value is 4.00. Then wait about one minute, and adjust the
+   *  potentiometer on the interface board.  Let the value stabilise
+   *  at around 4.00. At this time,the acidic calibration has been
+   *  completed and you can measure the pH value of an acidic
+   *  solution.
+   *
+   *  4) According to the linear characteristics of pH electrode
+   *  itself, after the above calibration,you can directly measure the
+   *  pH value of the alkaline solution. If you want to get better
+   *  accuracy, you can recalibrate it. Alkaline calibration use the
+   *  standard solution whose pH value is 9.18.  Also adjust the
+   *  potentiometer and let the value stabilise at around 9.18. After
+   *  this calibration, you can measure the pH value of an alkaline
+   *  solution.
+   *
+   * @image html dfrph.jpg
+   * @snippet dfrph.cxx Interesting
+   */
+
+  class DFRPH {
+  public:
+
+    /**
+     * DFRPH constructor
+     *
+     * @param pin Analog pin to use
+     * @param aref Analog reference voltage; default is 5.0 V
+     */
+    DFRPH(int pin, float aref=5.0);
+
+    /**
+     * DFRPH destructor
+     */
+    ~DFRPH();
+
+    /**
+     * Returns the voltage detected on the analog pin
+     *
+     * @return The detected voltage
+     */
+    float volts();
+
+    /**
+     * Specifies the offset determined from calibration.  The default
+     * is 0.0.
+     *
+     * @param offset The offset value to use
+     */
+    void setOffset(float offset);
+
+    /**
+     * Take a number of samples and return the detected pH value.  The
+     * default number of samples is 15.
+     *
+     * @param samples The number of samples to average over, default 15
+     * @return The pH value detected
+     */
+    float pH(unsigned int samples=15);
+
+  protected:
+    mraa::Aio m_aio;
+
+  private:
+    float m_aref;
+    // ADC resolution
+    int m_aRes;
+
+    // voltage offset
+    float m_offset;
+  };
+}
+
+