Crash on de-serializing GPX with Extensions

[TomQv]

this gpx-file causes a crash in DoReadGpx because of the extensions-blocks.
Tom

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<gpx xmlns="http://www.topografix.com/GPX/1/1" 
     xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3" 
     xmlns:wptx1="http://www.garmin.com/xmlschemas/WaypointExtension/v1" 
     xmlns:gpxtpx="http://www.garmin.com/xmlschemas/TrackPointExtension/v1" 
     creator="GPSMAP 62st" 
     version="1.1" 
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xsi:schemaLocation="http://www.topografix.com/GPX/1/1 
                         http://www.topografix.com/GPX/1/1/gpx.xsd 
                         http://www.garmin.com/xmlschemas/GpxExtensions/v3 
                         http://www8.garmin.com/xmlschemas/GpxExtensionsv3.xsd 
                         http://www.garmin.com/xmlschemas/WaypointExtension/v1 
                         http://www8.garmin.com/xmlschemas/WaypointExtensionv1.xsd 
                         http://www.garmin.com/xmlschemas/TrackPointExtension/v1 
                         http://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd">   <metadata>
        <link href="http://www.garmin.com">
            <text>Garmin International</text>
        </link>
        <time>2013-05-06T21:21:39Z</time>
    </metadata>
    <trk>
        <name>Aktueller Track: 06 MAI 2013 16:21</name>
        <trkseg>        
            <trkpt lat="47.7517450321" lon="14.3034374714">
                <ele>581.73</ele>
                <time>2013-05-06T14:22:32Z</time>
                <extensions>
                    <gpxtpx:TrackPointExtension>
                        <gpxtpx:atemp>24.5</gpxtpx:atemp>
                        <gpxtpx:hr>110</gpxtpx:hr>
                    </gpxtpx:TrackPointExtension>
                </extensions>
            </trkpt>
            <trkpt lat="47.7517618798" lon="14.3034445122">
                <ele>586.06</ele>
                <time>2013-05-06T14:22:37Z</time>
                <extensions>
                    <gpxtpx:TrackPointExtension>
                        <gpxtpx:atemp>24.5</gpxtpx:atemp>
                        <gpxtpx:hr>107</gpxtpx:hr>
                    </gpxtpx:TrackPointExtension>
                </extensions>
            </trkpt>
        </trkseg>
    </trk>
</gpx>

[xivk]

I added a regression test assuming it would fail but it passed. Will now test on Android.

[xivk]

Fails only on Android.

[xivk]

Garmin has extended the GPX V1.1 definition with it's own 'extensions':

http://www8.garmin.com/xmlschemas/GpxExtensions/v3/GpxExtensionsv3.xsd

Will have a look and see how this can be parsed (or ignored for now).