Fix copying of island names in SeaGenerator

The name tags of islands and land were not copied although it was intended. This happened when the SeaGenerator copied ways due to internal coastline error handling (anti-islands etc.).

git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3191 25d90789-57f7-4ee0-8453-03a3dfeeeb22