GEOS-5549: fixed up/down arrows in LayerGroups UI
Merge pull request #165 from svzdvd/GEOS5549-group-updown-fix

GEOS-5549: fixed up/down arrows in LayerGroups UI
 GEOS-5549: fixed up/down arrows in LayerGroups UI, follow up to fix annoying extra issues (arrows on all the time, visual alternation broken, error messages on the console
Merge branch 'master' of git://github.com/geoserver/geoserver