FIX: crash if building water industries over map border

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6490 8aca7d54-2c30-db11-9de9-000461428c89
FIX crash when building factories at map border

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6491 8aca7d54-2c30-db11-9de9-000461428c89
CHG: limit search when looking for places for city attractions and monuments

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6492 8aca7d54-2c30-db11-9de9-000461428c89