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/nmea_gps-i2c.c

@@ -0,0 +1,83 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 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.
+ */
+
+#include <unistd.h>
+#include <signal.h>
+
+#include "nmea_gps.h"
+#include "upm_utilities.h"
+
+bool shouldRun = true;
+
+const size_t bufferLength = 128;
+
+void sig_handler(int signo)
+{
+    if (signo == SIGINT)
+        shouldRun = false;
+}
+
+int main()
+{
+    signal(SIGINT, sig_handler);
+
+    //! [Interesting]
+
+    // Instantiate a NMEA_GPS UBLOX based i2c sensor on i2c bus 0 at
+    // address 0x42
+    nmea_gps_context sensor = nmea_gps_init_ublox_i2c(0, 0x42);
+
+    if (!sensor)
+    {
+        printf("nmea_gps_init_ublox_i2c() failed.\n");
+        return 1;
+    }
+
+    char buffer[bufferLength];
+    int rv = 0;
+
+    // loop, dumping NMEA data out as fast as it comes in
+    while (shouldRun)
+    {
+        if (!nmea_gps_data_available(sensor, 0))
+            upm_delay_ms(500);
+        else
+        {
+            if ((rv = nmea_gps_read(sensor, buffer, bufferLength)) >= 0)
+            {
+                int i;
+                for (i=0; i<rv; i++)
+                    printf("%c", buffer[i]);
+            }
+        }
+    }
+
+    //! [Interesting]
+
+    printf("Exiting\n");
+
+    nmea_gps_close(sensor);
+
+    return 0;
+}