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++/grove-grovelight.cxx

@@ -0,0 +1,49 @@
+/*
+ * Author: Brendan Le Foll <brendan.le.foll@intel.com>
+ * Contributions: Sarah Knepper <sarah.knepper@intel.com>
+ * Copyright (c) 2014 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 "grove.hpp"
+
+int
+main(int argc, char **argv)
+{
+//! [Interesting]
+    // Create the light sensor object using AIO pin 0
+    upm::GroveLight* light = new upm::GroveLight(0);
+
+    // Read the input and print both the raw value and a rough lux value,
+    // waiting one second between readings
+    while( 1 ) {
+        std::cout << light->name() << " raw value is " << light->raw_value() <<
+            ", which is roughly " << light->value() << " lux" << std::endl;
+        sleep(1);
+    }
+
+    // Delete the light sensor object
+    delete light;
+//! [Interesting]
+    return 0;
+}