fix #8631 - Make ParallelWays more robust to self-intersecting ways

git-svn-id: http://josm.openstreetmap.de/svn/trunk@5981 0c6e7542-c601-0410-84e7-c038aed88b3b
ParallelWayAction: handle nautical mile SoM + listen to preferences changes

git-svn-id: http://josm.openstreetmap.de/svn/trunk@5982 0c6e7542-c601-0410-84e7-c038aed88b3b
Merge branch 'master' into mirror