slide: Added slide potentiometer sensor C source

Added the C source for the flex sensor with necessary changes to cmake,
examples, and docs.

    * Renamed all files with groveslide to slide
    * Replaced all instances of groveslide with slide
    * Added C source for slide sensor
    * Updated all cmake files
    * Added C example for slide sensor
    * Split out slide sensor from grove library

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

src/slide/slide.hpp

@@ -0,0 +1,92 @@
+/*
+ * Authors: Brendan Le Foll <brendan.le.foll@intel.com>
+ *          Mihai Tudor Panu <mihai.tudor.panu@intel.com>
+ *          Sarah Knepper <sarah.knepper@intel.com>
+ * Copyright (c) 2014 - 2016 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 <string>
+#include <mraa/aio.hpp>
+
+namespace upm {
+
+/**
+ * @library slide
+ * @sensor slide
+ * @comname Slide Potentiometer
+ * @type ainput
+ * @man seeed
+ * @con analog
+ *
+ * @brief API for the Slide Potentiometer
+ *
+ * Basic UPM module for the slide potentiometer on analog that
+ * returns either a raw value or a scaled voltage value.
+ *
+ * @image html slide.jpeg
+ * @snippet slide.cxx Interesting
+ */
+class Slide {
+    public:
+        /**
+         * Analog slide potentiometer constructor
+         *
+         * @param pin Number of the analog pin to use
+         *
+         * @param ref_voltage Reference voltage the board is set to, as a floating-point value; default is 5.0V
+         */
+        Slide(unsigned int pin, float ref_voltage = 5.0);
+        /**
+         * Slide destructor
+         */
+        ~Slide();
+        /**
+         * Gets the raw value from the AIO pin
+         *
+         * @return Raw value from the ADC
+         */
+        float raw_value();
+        /**
+         * Gets the voltage value from the pin
+         *
+         * @return Voltage reading based on the reference voltage
+         */
+        float voltage_value();
+        /**
+         * Gets the board's reference voltage passed on object initialization
+         *
+         * @return Reference voltage the class was set for
+         */
+        float ref_voltage();
+
+        /* Gets the sensor name
+         *
+         * @return sensor name
+         */
+        std::string name() {return "Slide Potentiometer";}
+    private:
+        mraa_aio_context m_aio;
+        float m_ref_voltage;
+};
+}