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/hx711/hx711.hpp

@@ -0,0 +1,138 @@
+/*
+ * Author: Rafael da Mata Neri <rafael.neri@gmail.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 <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <mraa/gpio.h>
+
+namespace upm {
+     /**
+      * @brief HX711 24-bit ADC library
+      * @defgroup hx711 libupm-hx711
+      * @ingroup generic gpio electric
+      */
+
+     /**
+      * @library hx711
+      * @sensor hx711
+      * @comname HX711 Analog-to-Digital Converter
+      * @type electric
+      * @man generic
+      * @web http://www.dfrobot.com/image/data/SEN0160/hx711_english.pdf
+      * @con gpio
+      *
+      * @brief API for the HX711 Analog-to-Digital Converter
+      *
+      * HX711 is a precision 24-bit analog-to-digital converter (ADC)
+      * designed for weight scales and industrial control applications to
+      * interface directly with a bridge sensor. This module was tested on
+      * the Intel(R) Galileo Gen 2 board.
+      *
+      * @image html hx711.jpeg
+      * @snippet hx711.cxx Interesting
+      */
+      class HX711 {
+      public:
+            /**
+            * HX711 constructor
+            *
+            * @param data Defines the data pin
+            * @param sck Defines the clock pin
+            * @param gain Defines the gain factor
+            * Valid values are 128 or 64 for channel A; channel B works with a 32-gain factor only
+            */
+            HX711(uint8_t data, uint8_t sck, uint8_t gain = 128);
+
+            /**
+            * HX711 destructor
+            */
+            ~HX711();
+
+            /**
+            * Waits for the chip to be ready and returns a reading
+            *
+            * @return Raw ADC reading
+            */
+            unsigned long read();
+
+            /**
+            * Sets the gain factor; takes effect only after a call to read()
+            * channel A can be set for a 128 or 64 gain; channel B has a fixed 32-gain
+            * factor depending on the parameter; the channel is also set to either A or B
+            * @param gain Defines the gain factor
+            */
+            void setGain(uint8_t gain = 128);
+
+            /**
+            * Returns an average reading
+            * @param times Defines how many reading to do
+            * @return Average reading
+            */
+            unsigned long readAverage(uint8_t times = 10);
+
+            /**
+            * Returns (readAverage() - OFFSET)
+            * @param times Defines how many readings to do
+            * @return Current value without the tare weight
+            */
+            double getValue(uint8_t times = 10);
+
+            /**
+            * Returns getValue() divided by SCALE
+            * @param times Defines how many readings to do
+            * @return Raw value divided by a value obtained via calibration
+            */
+            float getUnits(uint8_t times = 1);
+
+            /**
+            * Sets the OFFSET value for the tare weight
+            * @param times Defines how many times to read the tare value
+            */
+            void tare(uint8_t times = 10);
+
+            /**
+            * Sets the SCALE value
+            * This value is used to convert the raw data to human-readable data (measurement units)
+            * @param scale Value obtained via calibration
+            */
+            void setScale(float scale = 1.f);
+       private:
+            mraa_gpio_context m_sckPinCtx; // Power Down and Serial Clock Input Pin
+            mraa_gpio_context m_dataPinCtx; // Serial Data Output Pin
+
+            uint8_t GAIN; // amplification factor
+            unsigned long OFFSET; // used for tare weight
+            float SCALE; // used to return weight in grams, kg, ounces, whatever
+
+
+            /**
+            * Sets the OFFSET value
+            * This value is subtracted from the actual reading (tare weight)
+            * @param scale Value obtained via calibration
+            */
+            void setOffset(long offset = 0);
+     };
+
+}