[josm_directupload] update eclipse project, build.xml, fix EDT violations

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29718 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
[josm_directupload] fix #josm7590 - correct use of OSM API URL in order to reuse known credentials + use of user-agent

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29719 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4