[josm_elevationprofile] makes plugin compile with Java 6 (again)

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29963 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
[josm_elevationprofile] Render elevation grid using tile framework

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29964 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4