Upload trace fail with a stack trace for WhereamI+ traces

[ramilehti]

When trying to upload a trace using the upload trace plugin and a trace created by WhereAmI
​http://www.symbianos.org/projects_mapping
I get the following stack trace.

java.lang.ClassCastException: java.lang.Float cannot be cast to java.lang.String

at org.openstreetmap.josm.io.GpxWriter.writeAttr(GpxWriter.java:70)
at org.openstreetmap.josm.io.GpxWriter.wayPoint(GpxWriter.java:238)
at org.openstreetmap.josm.io.GpxWriter.writeTracks(GpxWriter.java:156)
at org.openstreetmap.josm.io.GpxWriter.write(GpxWriter.java:54)
at org.openstreetmap.josm.plugins.DirectUpload.UploadDataGui.writeGpxFile(UploadDataGui.java:424)
at org.openstreetmap.josm.plugins.DirectUpload.UploadDataGui.upload(UploadDataGui.java:183)
at org.openstreetmap.josm.plugins.DirectUpload.UploadDataGui.access$300(UploadDataGui.java:56)
at org.openstreetmap.josm.plugins.DirectUpload.UploadDataGui$1.realRun(UploadDataGui.java:380)
at org.openstreetmap.josm.gui.PleaseWaitRunnable.run(PleaseWaitRunnable.java:101)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

Tracks created by Nokia Sports Tracker for example work.
You will find attached one such trace.

[stoecker]

Closed as duplicate of #2359.