[josm_plugins] remove org.json from plugins as being included into JOSM core 6484

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@30131 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
[josm-elevationprofile] update ant classpath

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@30132 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
[josm_simplifyarea] code simplification

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@30133 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4