examples: C/C++ examples use transitive dependencies

Updated the examples to comprehend transitive dependencies.  This means
that each example target will no longer have a giant list of -I includes
(the examples at the end of the list had includes for all previous
examples, upwards of 200 -I's on the command line).

    * Created a CMakeLists.txt in the upm/examples directory, moved
      common functionality to this level.
    * C/C++ examples now look to the filename for their dependency
      target name, ie; gas-mq2.cxx adds a dependency to the 'gas' target
    * Updated a handful of C/C++ example names to reflect this
    * Example CMake flow - glob the list of files, add targets for any
      special case examples, then att targets for all the rest

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

examples/c++/ads1x15-adc-sensor.cxx

@@ -0,0 +1,80 @@
+/*
+ * Author: Henry Bruce <henry.bruce@intel.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.
+ */
+
+#include <unistd.h>
+#include <iostream>
+#include "ads1015.hpp"
+#include "mraa/gpio.hpp"
+
+#define EDISON_I2C_BUS 1
+#define FT4222_I2C_BUS 0
+#define EDISON_GPIO_SI7005_CS 20
+
+
+//! [Interesting]
+// Simple example of using IADC to determine
+// which sensor is present and return its name.
+// IADC is then used to get readings from sensor
+
+
+upm::IADC* getADC()
+{
+   upm::IADC* adc = NULL;
+   try {
+      adc = new upm::ADS1015(EDISON_I2C_BUS);
+      mraa::Gpio gpio(EDISON_GPIO_SI7005_CS);
+      gpio.dir(mraa::DIR_OUT_HIGH);
+      return adc;
+   } catch (std::exception& e) {
+      std::cerr << "ADS1015: " << e.what() << std::endl;
+   }
+   return adc;
+}
+
+int main ()
+{
+   upm::IADC* adc = getADC();
+   if (adc == NULL) {
+      std::cout << "ADC not detected" << std::endl;
+      return 1;
+   }
+   std::cout << "ADC " << adc->getModuleName() << " detected. " ;
+   std::cout << adc->getNumInputs() << " inputs available" << std::endl;
+   while (true) {
+      for (unsigned int i=0; i<adc->getNumInputs(); ++i) {
+         std::cout << "Input " << i;
+         try {
+            float voltage = adc->getVoltage(i);
+            std::cout << ": Voltage = " << voltage << "V" << std::endl;
+         } catch (std::exception& e) {
+            std::cerr << e.what() << std::endl;
+         }
+      }
+      sleep(1);
+   }
+   delete adc;
+   return 0;
+}
+
+//! [Interesting]