ignore obsolete "lua" attributes in ancient data files.
fix a small bug in the mechanism for reading deprecated attrib_types.
bugfix: USE snowman did not check that the unit actually owned a snowman, causing a unit to have negative snowmen in turn 629 (exploit).
bugfix: making clones help with upkeep.
https://bugs.eressea.de/view.php?id=1560
Merge remote-tracking branch 'eressea/master'
bugfixe give_cmd (cannot give more persons than the unit has).
Merge pull request #73 from badgerman/master

ongoing bugfixing