flex: initial implementation

Implements the flex analog sensor.  See
http://bildr.org/2012/11/flex-sensor-arduino/
for wiring instructions.

Signed-off-by: Zion Orent <zorent@ics.com>
Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: John Van Drasek <john.r.van.drasek@intel.com>

src/flex/flex.h

@@ -0,0 +1,71 @@
+/*
+ * Author: Zion Orent <zorent@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 <string>
+#include <mraa/aio.h>
+
+namespace upm {
+
+  /**
+   * @brief UPM module for the Spectra Symbol Flex sensor
+   * @defgroup flex libupm-flex
+   * @ingroup sparkfun analog flex
+   */
+
+  /**
+   * @sensor flex
+   * @library flex
+   * @name Spectra Symbol Flex sensor
+   * @category flex
+   * @manufacturer sparkfun
+   * @connection analog
+   *
+   * @brief C++ API for the Spectra Symbol Flex sensor
+   *
+   * @snippet flex.cxx Interesting
+   */
+  class Flex {
+  public:
+    /**
+     * Flex sensor constructor
+     *
+     * @param pin analog pin to use
+     */
+    Flex(int pin);
+    /**
+     * Flex Destructor
+     */
+    ~Flex();
+    /**
+     * @return the analog flex value
+     */
+    int value();
+
+  private:
+    mraa_aio_context m_aio;
+  };
+}
+
+