nmea_gps: add support for ubloc I2c reading of NMEA data

These changes allow NMEA data to be read via I2C on UBLOX compliant
devices that support this capability, such as the LEA-6H based GPS
shield from DFRobot.

It adds a new init() function to the C code, and a new constructor to
the C++ code. It also adds 5 new examples for C, C++, Javascript,
Python, and Java.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/c++/CMakeLists.txt

@@ -317,3 +317,4 @@ if (OPENZWAVE_FOUND)
   add_custom_example (aeotecdsb09104-example aeotecdsb09104.cxx ozw)
   add_custom_example (tzemt400-example tzemt400.cxx ozw)
 endif()
+add_custom_example (nmea_gps_i2c_example-cxx nmea_gps_i2c.cxx nmea_gps)

examples/c++/nmea_gps_i2c.cxx

@@ -0,0 +1,69 @@
+/*
+ * 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 <iostream>
+#include <signal.h>
+
+#include "nmea_gps.hpp"
+
+using namespace std;
+
+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
+  upm::NMEAGPS *sensor = new upm::NMEAGPS(0, 0x42);
+
+  // loop, dumping NMEA data out as fast as it comes in
+  while (shouldRun)
+    {
+      if (sensor->dataAvailable(0))
+        usleep(100);
+      else
+        cout << sensor->readStr(bufferLength);
+    }
+
+//! [Interesting]
+
+  cout << "Exiting" << endl;
+
+  delete sensor;
+
+  return 0;
+}