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/gas/mq6.hpp

@@ -0,0 +1,75 @@
+/*
+ * 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 "gas.hpp"
+
+namespace upm {
+  /**
+   * @library gas
+   * @sensor mq6
+   * @comname DFRobot MQ6 LPG Gas Sensor
+   * @type gaseous
+   * @man dfrobot
+   * @con analog
+   *
+   * @brief API for the DFRobot MQ6 LPG Gas Sensor
+   *
+   * The MQ6 Gas Sensor module is useful for detecting LPG,
+   * iso-butane, propane, and LNG concentrations in the air.  It has a
+   * detection range of 200-10000 ppm.
+   *
+   * For optimum use, it requires calibration after a pre-heat time of
+   * at least 24 hours.  See the datasheet for details.
+   *
+   * @image html mq2-5.jpeg
+   * @snippet mq6.cxx Interesting
+   */
+    class MQ6 : public Gas {
+        public:
+            /**
+             * MQ6 constructor
+             *
+             * @param gasPin Analog pin where the sensor is connected
+             */
+            MQ6 (int gasPin);
+
+            /**
+             * MQ6 destructor
+             */
+            ~MQ6 ();
+
+            /**
+             * Returns the name of the sensor
+             */
+            std::string name()
+            {
+                return m_name;
+            }
+        private:
+            std::string m_name;
+    };
+}