#8972 - Receiving nullpointer exception when loading map style whose paths are relative to zip root


git-svn-id: http://josm.openstreetmap.de/svn/trunk@6151 0c6e7542-c601-0410-84e7-c038aed88b3b
see #8972 - fix path separator


git-svn-id: http://josm.openstreetmap.de/svn/trunk@6152 0c6e7542-c601-0410-84e7-c038aed88b3b