create .empty files in vizSkeleton so that empty dirs can be committed
create .empty files in vizSkeleton so that empty dirs can be committed

ldecicco-USGS/vizlab,lindsaycarr/vizlab,USGS-VIZLAB/vizlab,jiwalker-usgs/vizlab,USGS-VIZLAB/vizlab,lindsaycarr/vizlab,ldecicco-USGS/vizlab,jiwalker-usgs/vizlab,jiwalker-usgs/vizlab,ldecicco-USGS/vizlab,aappling-usgs/vizlab,lindsaycarr/vizlab,aappling-usgs/vizlab,USGS-VIZLAB/vizlab,aappling-usgs/vizlab