JsonRideFile XDATA support

.. added a new 'XDATA' element for the JsonRideFile and
   RideFile classes.

.. this allows ride file readers to extract and load any
   time series data that doesn't neccessarily fit into
   the usual data points.

.. this was added to support weather data from FIT files
   and also to support 3rd party merging data with the
   GC supported data.

.. ** IMPORTANT ** the XDATA segment is added at the END
   of the JSON format. So older parsers will fail to read
   but will have loaded all data already (i.e. they will
   fail gracefully enough)

   This means files with XDATA can be read by earlier
   versions of GC, but the XDATA will be discarded.

src/FileIO/RideFile.cpp

@@ -768,11 +768,68 @@ RideFile *RideFileFactory::openRideFile(Context *context, QFile &file,
 
         //foreach(RideFile::seriestype x, result->arePresent()) qDebug()<<"present="<<x;
 
+        // sample code for using XDATA, left here temporarily till we have an
+        // example of using it in a ride file reader
+#if 0
+
+        // ADD XDATA TO RIDEFILE
+
+        // For testing xdata, this code just adds an xdata series
+        // XDataSeries *xdata = new XDataSeries();
+        // xdata->name = "SPEED";
+        // xdata->valuename << "SPEED";
+        // for(int i=0; i<100; i++) {
+        // XDataPoint *p = new XDataPoint();
+        // p->km = i;
+        // p->secs = i;
+        // p->number[0] = i;
+        // xdata->datapoints.append(p);
+        // }
+        // result->addXData("SPEED", xdata);
+
+        // DEBUG OUTPUT TO SHOW XDATA LOADED FROM RIDEFILE
+        // for testing, print out what we loaded
+        if (result->xdata_.count()) {
+
+            // output the xdata series
+            qDebug()<<"XDATA";
+
+            QMapIterator<QString,XDataSeries*> xdata(result->xdata());
+            xdata.toFront();
+            while(xdata.hasNext()) {
+
+                // iterate
+                xdata.next();
+
+                XDataSeries *series = xdata.value();
+
+                // does it have values names?
+                if (series->valuename.isEmpty()) {
+                    qDebug()<<"empty xdata"<<series->name;
+                    continue;
+                } else {
+                    qDebug()<<"xdata" <<series->name<<series->valuename<<series->datapoints.count();
+                }
+
+                // samples
+                if (series->datapoints.count()) {
+                    foreach(XDataPoint *p, series->datapoints)
+                        qDebug()<<"sample:"<<p->secs<<p->km<<p->number[0]<<p->number[1];
+                }
+            }
+        }
+#endif
     }
 
     return result;
 }
 
+void
+RideFile::addXData(QString name, XDataSeries *series)
+{
+    xdata_.insert(name, series);
+}
+
 QStringList RideFileFactory::listRideFiles(const QDir &dir) const
 {
     QStringList filters;