(ADD) scale up or down tool icons with entry in themes.tab

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6994 8aca7d54-2c30-db11-9de9-000461428c89
(ADD) scale up or down tool icons with entry in themes.tab

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6995 8aca7d54-2c30-db11-9de9-000461428c89