[josm_elevationprofile] Bugfix: Panel did not show complete track in some cases

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29981 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
[josm_elevationprofile]: Show SRTM indicator, minor UI improvements

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29982 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4