Add workaround for issues with GPX generation in IE11
Add workaround for issues with GPX generation in IE11

This works around an issue in tyrasd/jxon by repairing the invalid XML name
space declarations in the GPX data and should thus yield usable GPX files
in IE11, too.

sosm/osrm-frontend,sosm/osrm-frontend,sosm/osrm-frontend