Turn assertions on for debug builds!  (Why were they off?!?!)
Add assertion and check for missed case in dataobj/dingliste.cc (dingliste_t::add)
Merge branch 'ncn-devel' of git://github.com/neroden/simutrans.git into 112.x-private-car-merge
Revert probably-erroneous bit of last commit.
Merge branch 'ncn-devel' of git://github.com/neroden/simutrans.git into 112.x-private-car-merge